Can I use VMware's VMware Server or Connectix's Virtual PC for Windows to run Exchange Server? Does Microsoft support such a configuration?
I couldn't find any current official Microsoft statement about whether the company supports this type of setup, which I suspect means that it doesn't. You certainly can run Exchange with the products you mention—and run it reasonably well if you dedicate enough RAM to the virtual machine. These virtual machines can be useful in test labs, in which performance and sustained runtime aren't crucial. However, I wouldn't recommend using Exchange with such machines in a production environment.