I have a dual-boot setup on my machine Ubuntu Linux / Windows XP and I often access my Linux Ext3 partitions from Windows using this tool:

fs-driver.org/

It's the most simple thing you can install, and afterward, you will have read-write access to your Ext2/Ext3 partitions.

I can't say much for performance, but that is totally understandable. It's more for convenience sake. But FYI, here are how fast my Liferay portal source builds (portal source "ant all") are:

Intel Core2 Duo 2.33 GHz, 2GB RAM

Windows XP / NTFS - ~8 minutes

Windows XP / Ext3 (fs-driver) - over 12 minutes

Ubuntu Linux / Ext3 - ~2 1/2 minutes