I've been being asked this a lot recently, so I'm going to blog it. Also a wiki on it.
5.1
To see a listing of available web services (v 5.1), you can go to the following URL with Liferay running locally:
http://localhost:8080/tunnel-web/axis
It will also give you access to the WSDL files. It looks like this:
And now... Some Services
- Portal_AccountService (wsdl)
- Portlet_IG_IGImageService (wsdl)
- deleteImage
- getImages
- getImageByFolderIdAndNameWithExtension
- getImageByLargeImageId
- getImageBySmallImageId
- deleteImageByFolderIdAndNameWithExtension
- getImage
- Portlet_SC_SCFrameworkVersionService (wsdl)
- addFrameworkVersion
- addFrameworkVersion
- deleteFrameworkVersion
- getFrameworkVersion
- getFrameworkVersions
- getFrameworkVersions
- updateFrameworkVersion
- Portlet_Shopping_ShoppingItemService (wsdl)
- addBookItems
- deleteItem
- getItem
- Portlet_DL_DLFolderService (wsdl)
- getFolderId
- getFolder
- getFolder
- updateFolder
- addFolder
- addFolder
- deleteFolder
- deleteFolder
- getFolders
- copyFolder
- reIndexSearch
- Portlet_DL_DLFileShortcutService (wsdl)
- addFileShortcut
- addFileShortcut
- deleteFileShortcut
- getFileShortcut
- updateFileShortcut
- Portlet_Polls_PollsVoteService (wsdl)
- addVote
- Portlet_SC_SCProductEntryService (wsdl)
- addProductEntry
- addProductEntry
- deleteProductEntry
- getProductEntry
- updateProductEntry
- Portlet_Announcements_AnnouncementsDeliveryService (wsdl)
- updateDelivery
- Portlet_Workflow_WorkflowDefinitionService (wsdl)
- getDefinition
- addDefinition
- addDefinition
- addDefinition
- addDefinitionResources
- addDefinitionResources
- Portlet_Shopping_ShoppingCouponService (wsdl)
- addCoupon
- deleteCoupon
- getCoupon
- updateCoupon
- search
- Portal_UserGroupService (wsdl)
- getUserGroup
- getUserGroup
- addUserGroup
- addGroupUserGroups
- deleteUserGroup
- getUserUserGroups
- unsetGroupUserGroups
- updateUserGroup
- Portlet_Announcements_AnnouncementsEntryService (wsdl)
- updateEntry
- addEntry
- deleteEntry
- AdminService (wsdl)
- AdminService
- Version (wsdl)
- getVersion
- Portlet_Workflow_WorkflowInstanceService (wsdl)
- signalInstance
- signalToken
- addInstance
- Portal_WebsiteService (wsdl)
- addWebsite
- deleteWebsite
- getWebsite
- getWebsites
- updateWebsite
- Portlet_MB_MBCategoryService (wsdl)
- getCategory
- addCategory
- addCategory
- deleteCategory
- getCategoriesCount
- updateCategory
- subscribeCategory
- unsubscribeCategory
- getCategories
- Portlet_Bookmarks_BookmarksEntryService (wsdl)
- openEntry
- updateEntry
- addEntry
- addEntry
- getEntry
- deleteEntry
- Portal_PermissionService (wsdl)
- setRolePermission
- hasGroupPermission
- hasUserPermission
- hasUserPermissions
- setGroupPermissions
- setGroupPermissions
- setOrgGroupPermissions
- unsetRolePermissions
- setRolePermissions
- setUserPermissions
- unsetRolePermission
- unsetRolePermission
- unsetUserPermissions
- checkPermission
- Portal_MembershipRequestService (wsdl)
- deleteMembershipRequests
- addMembershipRequest
- getMembershipRequest
- updateStatus
- Portal_EmailAddressService (wsdl)
- deleteEmailAddress
- updateEmailAddress
- getEmailAddress
- addEmailAddress
- getEmailAddresses
- Portal_PortletPreferencesService (wsdl)
- deleteArchivedPreferences
- Portal_LayoutService (wsdl)
- addLayout
- deleteLayout
- deleteLayout
- setLayouts
- updateLookAndFeel
- updateName
- updateName
- updateParentLayoutId
- updateParentLayoutId
- updatePriority
- updatePriority
- getLayoutName
- getLayoutReferences
- unschedulePublishToLive
- unschedulePublishToRemote
- updateLayout
- Portlet_Workflow_WorkflowComponentService (wsdl)
- getTask
- deploy
- getCurrentTasks
- getCurrentTasksXml
- getDefinition
- getDefinitions
- getDefinitionsXml
- getDefinitionsCount
- getDefinitionsCountXml
- getDefinitionXml
- getInstances
- getInstancesCount
- getInstancesCountXml
- getInstancesXml
- getTaskXml
- getTaskFormElements
- getTaskFormElementsXml
- getTaskTransitions
- getTaskTransitionsXml
- getUserTasks
- getUserTasksCount
- getUserTasksCountXml
- getUserTasksXml
- signalInstance
- signalToken
- startWorkflow
- Portal_PortalService (wsdl)
- test
- Portlet_Journal_JournalStructureService (wsdl)
- addStructure
- addStructure
- deleteStructure
- getStructure
- updateStructure
- Portlet_Journal_JournalArticleService (wsdl)
- getArticle
- removeArticleLocale
- removeArticleLocale
- updateContent
- Portal_OrganizationService (wsdl)
- getUserOrganizations
- getOrganizationId
- addOrganization
- addGroupOrganizations
- addPasswordPolicyOrganizations
- deleteOrganization
- setGroupOrganizations
- unsetGroupOrganizations
- unsetPasswordPolicyOrganizations
- updateOrganization
- getOrganization
- Portal_GroupService (wsdl)
- updateGroup
- updateGroup
- addGroup
- addGroup
- addRoleGroups
- deleteGroup
- getOrganizationsGroups
- getUserGroupsGroups
- hasUserGroup
- searchCount
- setRoleGroups
- unsetRoleGroups
- updateFriendlyURL
- updateWorkflow
- search
- getGroup
- getGroup
- Portlet_Bookmarks_BookmarksFolderService (wsdl)
- getFolder
- updateFolder
- addFolder
- addFolder
- deleteFolder
- Portlet_DL_DLFileEntryService (wsdl)
- addFileEntry
- addFileEntry
- deleteFileEntry
- deleteFileEntry
- deleteFileEntryByTitle
- getFileEntries
- getFileEntry
- getFileEntryByTitle
- lockFileEntry
- unlockFileEntry
- updateFileEntry
- Portlet_Tags_TagsSourceService (wsdl)
- Portal_ListTypeService (wsdl)
- getListType
- getListTypes
- validate
- validate
- Portlet_Shopping_ShoppingCategoryService (wsdl)
- getCategory
- addCategory
- addCategory
- deleteCategory
- updateCategory
- Portlet_Cal_CalEventService (wsdl)
- deleteEvent
- getEvent
- updateEvent
- addEvent
- addEvent
- Portal_UserService (wsdl)
- getUserById
- getDefaultUserId
- addUser
- deleteUser
- updatePassword
- addGroupUsers
- addOrganizationUsers
- addPasswordPolicyUsers
- addRoleUsers
- addUserGroupUsers
- updateOrganizations
- getUserByEmailAddress
- getUserByScreenName
- deleteRoleUser
- getGroupUsers
- getRoleUsers
- getUserIdByEmailAddress
- getUserIdByScreenName
- hasGroupUser
- hasRoleUser
- setRoleUsers
- setUserGroupUsers
- unsetGroupUsers
- unsetOrganizationUsers
- unsetPasswordPolicyUsers
- unsetRoleUsers
- unsetUserGroupUsers
- updateActive
- updateAgreedToTermsOfUse
- updateLockout
- updateOpenId
- updatePortrait
- updateScreenName
- updateUser
- updateUser
- Portal_RoleService (wsdl)
- getRole
- getRole
- hasUserRole
- getGroupRole
- deleteRole
- addRole
- addUserRoles
- getGroupRoles
- getUserGroupRoles
- getUserRelatedRoles
- getUserRoles
- hasUserRoles
- unsetUserRoles
- updateRole
- Portlet_IG_IGFolderService (wsdl)
- addFolder
- addFolder
- copyFolder
- deleteFolder
- getFolder
- getFolder
- getFolders
- updateFolder
- Portlet_Polls_PollsQuestionService (wsdl)
- addQuestion
- addQuestion
- deleteQuestion
- getQuestion
- updateQuestion
- Portal_ContactService (wsdl)
- Portal_PhoneService (wsdl)
- addPhone
- deletePhone
- getPhone
- getPhones
- updatePhone
- Portal_PortletService (wsdl)
- updatePortlet
- getWARPortlets
- Portlet_Workflow_WorkflowTaskService (wsdl)
- Portal_OrgLaborService (wsdl)
- addOrgLabor
- deleteOrgLabor
- getOrgLabor
- getOrgLabors
- updateOrgLabor
- Portal_AddressService (wsdl)
- addAddress
- deleteAddress
- getAddresses
- updateAddress
- getAddress
- Portal_CountryService (wsdl)
- addCountry
- getCountries
- getCountries
- getCountry
- Portlet_Blogs_BlogsEntryService (wsdl)
- getCompanyEntries
- getGroupEntries
- getOrganizationEntries
- getEntry
- getEntry
- deleteEntry
- Portal_PasswordPolicyService (wsdl)
- addPasswordPolicy
- deletePasswordPolicy
- updatePasswordPolicy
- Portlet_MB_MBBanService (wsdl)
- addBan
- deleteBan
- Portlet_Shopping_ShoppingOrderService (wsdl)
- getOrder
- sendEmail
- completeOrder
- deleteOrder
- updateOrder
- updateOrder
- Portal_RegionService (wsdl)
- addRegion
- getRegions
- getRegions
- getRegions
- getRegions
- getRegion
- Portlet_Journal_JournalFeedService (wsdl)
- addFeed
- addFeed
- deleteFeed
- deleteFeed
- getFeed
- getFeed
- updateFeed
- Portlet_Tags_TagsPropertyService (wsdl)
- addProperty
- addProperty
- getPropertyValues
- deleteProperty
- updateProperty
- getProperties
- Portlet_Ratings_RatingsEntryService (wsdl)
- updateEntry
- deleteEntry
- Portlet_MB_MBMessageService (wsdl)
- addMessage
- addMessage
- addMessage
- addMessage
- updateMessage
- deleteDiscussionMessage
- deleteMessage
- getCategoryMessages
- getCategoryMessagesCount
- getMessageDisplay
- subscribeMessage
- unsubscribeMessage
- updateDiscussionMessage
- getMessage
- Portlet_SC_SCProductVersionService (wsdl)
- addProductVersion
- addProductVersion
- deleteProductVersion
- getProductVersion
- getProductVersions
- getProductVersionsCount
- updateProductVersion
- Portlet_Tags_TagsEntryService (wsdl)
- updateEntry
- updateEntry
- searchCount
- mergeEntries
- searchAutocomplete
- addEntry
- addEntry
- search
- search
- deleteEntry
- getEntries
- getEntries
- Portlet_Tasks_TasksReviewService (wsdl)
- approveReview
- rejectReview
- updateReviews
- Portal_LayoutSetService (wsdl)
- updateLookAndFeel
- updateVirtualHost
- Portlet_SC_SCLicenseService (wsdl)
- addLicense
- deleteLicense
- getLicense
- updateLicense
- Portal_ClassNameService (wsdl)
- getClassName
- getClassName
- Portal_UserGroupRoleService (wsdl)
- addUserGroupRoles
- addUserGroupRoles
- deleteUserGroupRoles
- deleteUserGroupRoles
- Portlet_Reports_ReportsEntryService (wsdl)
- Portal_PluginSettingService (wsdl)
- updatePluginSetting
- Portal_ResourceService (wsdl)
- getResource
- Portlet_Tasks_TasksProposalService (wsdl)
- deleteProposal
- addProposal
- addProposal
- updateProposal
- Portlet_Wiki_WikiNodeService (wsdl)
- addNode
- addNode
- deleteNode
- subscribeNode
- unsubscribeNode
- updateNode
- getNode
- getNode
- Portlet_MB_MBThreadService (wsdl)
- moveThread
- Portlet_Journal_JournalTemplateService (wsdl)
- deleteTemplate
- getStructureTemplates
- getTemplate
- Portlet_Wiki_WikiPageService (wsdl)
- addPageAttachments
- deletePage
- deletePageAttachment
- subscribePage
- unsubscribePage
- getNodePages
- getNodePagesRSS
- getPagesRSS
- getPage
- getPage
- Portlet_Announcements_AnnouncementsFlagService (wsdl)
- deleteFlag
- getFlag
- addFlag
- Portlet_Tags_TagsAssetService (wsdl)
- deleteAsset
- getAsset
- getAssetsRSS
- getAssetTypes
- getCompanyAssetDisplays
- getCompanyAssets
- getCompanyAssetsCount
- getCompanyAssetsRSS
- incrementViewCounter
- searchAssetDisplays
- searchAssetDisplaysCount
- updateAsset
- Portal_CompanyService (wsdl)
- addCompany
- updateCompany
- updateCompany
- updateSecurity
- updateDisplay
Pre 5.0
Pre-5.0, you can get a similar listing here:

