So, as John points out in a comment to my last post, I have discovered that Microsoft Virtual PC 2007 doesn't support guest 64 bit operating systems even if it is running on a 64 bit system. Bugger! Ok, so I've learnt something today.
It seems that Sun has something called Virtual Box which appears to support 64 bit guest operating systems and seems to be all the rage with the Linux crowd. I think perhaps I'll try VM Server which is also free and appears to be more supported at least in the Windows world.
Hey, I've got plenty of time, I've only just completed the download of the second SBS 2008 ISO DVD. You do need something to do during these long downloads don't you? Maybe like get a life as my mother would say!