If you're trying the Resharper 4 beta nightly builds, I just thought I'd warn that I had trouble with build 775 from 11 Apr 2008, which is currently the newest build marked "Works here". When I installed it, the Resharper items, such as "Find Usages", were disabled in the context menu. I found the issue discussed in the Jetbrains forums, and they said they fixed it in a later build.
Now, I'm using build 780 from 18 Apr 2008, and it's working well for me so far.