Thanks to this posting Installing Ubuntu 8.04 under Microsoft Virtual PC 2007, and specifically the comment from Helge, (F4 and F6 plus some command line incantations) I have Ubuntu working on Virtual PC.
After installing, the comment on editing the kernel boot params is also required reading.
Unix is not meant to be easy I suppose.
This post from Mike on Virtually Vista is a great help.
For those on Toshiba M400 beasties, I’ve found that the Toshiba RAID driver 1.9.15.0 in combination with the BIOS 3.40 make QuickTime, iTunes and Virtual PC 2007 work well. Other HDD drivers installed after 1.9.15.0 do weird, unexplainable and unprintable things.