Personaly, I doubt that Virtual PC would be a good solution, because access to to USB devices is likely to be tricky. Linux will need raw access to the USB device, but as soon as you insert a USB key into the port, windows will claim it and mount the file system. Even if you get windows to release the device, there will probably be security reasons why windows won't want to grant the raw access linux needs.
IMHO, a much more straightforward option would be to boot a
knoppix disc, and run linux that way. Once the system is booted you get a good choice of GUI and command line partioning tools. I recommend
gparted that is also avalable as a
dedicated bootable CD