Hi,
Yes, the July07 version of GAX and GAT work ok on VS2008. If you have a previous version of GAX/GAT installed you would need to carefully uinstall all guidance packages and GAT/GAX before trying to attempt to install the July bits. Often, a failed or not clean uninstall causes GAX to be in a corrupt state.
The July07 version of GAX can run on VS2005 or VS2008, but *not* both at the same time (side-by-side GAX is not supported). So if you've a box already containing VS2005 and GAX installed, you will need to uninstall GAX and re-install once VS2008 is installed. This is so you get asked at GAX installation time which version of VS you want to install to. If you have only VS2005 or VS2008 you won't be asked anything and the GAX installer will just install on the only currently VS version installed. If you have both VS versions installed, you will get an extra UI step in GAX installation where you would be asked which version you want to install to (please pay attention to that screen as when in a hurry and pressing "next", "next", you can easily miss it).
If you have any issues while trying to get GAX working on VS2008 please post them here on a separate post specifying what issue you're facing.
HTH,
-Victor.