So Eclipse Galileo doesn't support GWT 1.6.4 fully yet, so I had to use 3.5 (Ganymede).
Download Eclipse Ganymede...
to add plug-ins go to Help...Software Updates...Available Software...Add Sites...
Add some optional plug-ins (we use google, maven, subclipse)
Google -> http://dl.google.com/eclipse/plugin/3.4
Maven -> http://m2eclipse.sonatype.org/update/
Subclipse -> http://subclipse.tigris.org/update_1.6.x
I did have an issue where the installer would say it couldn't find the repositories so it wouldn't install. In that case I deleted my added site and added it again...then it seemed to install.
I also ran the eclipse project update the same way.