I installed Resharper 3.0.2 with VS2008 RTM today and had a problem related to UAC. I am one of those crazy developers who actually runs with UAC turned on (that discussion is for another time and place) and when I installed Resharper today I got an error when it tried to register with VS during the install. It said that it needed elevated privileges to do this.. and then it went on with the install. When it was done I could bring up VS and it initialized Resharper, but there was no Resharper menu option and no way to get to any of the Resharper settings or menus.
I remedied this problem by opening a command window as Administrator and then running the Resharper install again as a repair from the command line, and this time it successfully registered Resharper in VS and all seems to be ok. I would think that the install script should prompt to elevate privileges so that it can do it's work successfully, but in the meantime I thought my solution might help someone else.