You probably would have to fire that 2003 server license up to be able to download the VSR2. I haven't used the VPC but the VSR2 probably is a better product, if you can get it working on Vista. Here's an article I saw about it.
http://blogs.msdn.com/virtual_pc_guy/archive/2006/10/10/Installing-Virtual-Server-2005-R2-on-Vista-RC1-_2F00_-RC2.aspx
Server 2003 was a little bit over my head.... I just wanted something "legal" that I knew for sure didn't have any viruses... ;)
LOL!