If you haven't seen VirtualBox yet, check out this YouTube video that someone did to show off Windows XP running in a VirtualBox environment on top of PCLinuxOS.  I wish they would have done a little bit more to showcase VirtualBox.  This 8+ minute video shows mostly opening and running a few apps, making the Windows XP VM 'wobble', etc.  I wass hoping for the video to show us a little more of the VirtualBox interface.  But, you get the picture.

Check it out, here.