If you're planning on participating in the TRINUG VS2008 InstallFest later this month, please be certain to have completely UN-installed any VS2008/.Net 3.5 prerelease software that you may have installed on your computer. Scott Guthrie has a blog post with a good list and order to go through to uninstall.
Microsoft DE (And all around nice guy) Joe Healy also has a list, which includes a few notes on what do do if things don't go smoothly.
I personally had no issues following Scott's list and am now happily running VS2008 and .Net 3.5.
** Just a note that we've pretty much reached our capacity for the TRINUG event. We are using a waiting list so please feel free to sign up and we'll let you know if a spot opens up. (If you are not going to be able to attend please let us know as well. You must be present to participate in the offer)