I installed Windows 7 RC in VMWare Fusion today (on an iMac with 2G of memory running Mac OS X 10.4). I followed the instructions on this post on the Team Fusion blog. "Windows Easy Install" blue-screened the guest machine so I tried a custom install which worked fine.
I then installed the Visual Studio 2010 beta and found this was very sluggish with a lot of display problems. Configuring the guest machine with 3D display switched off improved the performance and fixed the display issues.