Windows Vista will install on Virtual PC 2004. However, it seems to be pretty much unuseable, as it just seems to lock the CPU useage at 100%. If anyone has found differently, or knows a solution to that I'd be very interested to hear it.

If anyone wants to try it for themselves, you need to boot up the virtual machine with a Win98 or ME Startup floppy first and Fdisk the virtual drive (there is no need to format it). Vista cannot be installed otherwise.

Allow a good couple of hours for the install. And after it's done, you'll only get 800 x 600 resoultion with 4-bit colour until the Virtual Machine Additions are installed (from the Action menu).