The latest version of Liferay IDE version 1.1 has just been released to the update sites. To see a list of the new features and improvements take a look at the Liferay IDE 1.1 New and Noteworthy.
If you have previously installed Liferay IDE you can just use "Help > Check for Updates" and you should be offered the upgrade.
If you have not installed anything before you can add Liferay IDE to your Eclipse installation from one of the following update-sites:
If you have any trouble with upgrading or have any questions about the new features, feel free to ask a question over in the Liferay IDE forums. Also, I should be posting another update on the blog once I've had a chance to refresh the Liferay IDE wiki pages as well as add some additional documentation for some new and enhanced features.
Lastly check this wiki page for the Liferay IDE 1.5 Plan that will cover upcoming features in the next version of the Eclipse plug-ins.