If anyone is thinking of installing Vista, but would like to still be able to use Virtual Server, I can confirm that Virtual Server R2 SP1 Beta 2 runs great on the RC1 build under IIS 7. I am running on a dual-core AMD x64, and it currently only has 1GB of RAM while I wait for an upgrade to arrive. This is a great way to use Vista, but maintain assured compatability with existing solutions/software via virtual machines.
The last two times that I have installed Virtual Server R2, it has been SP1 Beta 1 and then Beta 2. Each time the install was simple, but when I first attempted to navigate to the Admin homepage, I recieved a login prompt. Very frustrating, to say the least. Each time I have resolved it by Googling and it was a pain to find the (simple) answer. The answer is easy: Add the address of the panel to your "Intranet Zone" in IE. This is an IE issue, not a Virtual Server issue from what I can tell.
Here is the link that helped me out and that explains the problem. I am putting this blog out here so that when I look for it again, it will be right here waiting for me.