David Musgrave has been maintaining a monster resource at Developing for Dynamics GP, which has
1. System Requirements
2. Product Downloads
3. Upgrade Documentation
4. SDK Links
5. GP Service Pack Links
and more …. for GP 9.0, GP 10.0 and GP 2010 all in one page.
I looked at the page before regarding the Developer KB articles, but just found out that David has been storing all the other valuable information as well. Should definitely save time for that rare occasion when you just cant seem to find the download link you are looking for.