Here is a ext2 file system driver for Windows:
http://fs-driver.org/
Ext3 is backwards compatible, so you can still mount it
as an ext2 file systems. Since fs-driver opearates in
the Windows kernel as an IFS, it should offer excellent
performance and compatibility with other win32 tools.
The only problem I see is that the current incarnation
ignores file ownership/group.
Pity I stopped using ext2/3 many moons ago...
- Raja