Virtual PC 2007 (
free download link here) would likely do the trick, but I've never run it on Windows server 2008, only on Server 2003 (which is the last server edition that MS lists as supported).
As for the system requirements, technically you far exceed the specifications necessary.
There are search results that list Server 2008 as being able to run Virtual PC, but many of them mention network connection issues.
YMMV.