Running Windows XP in a virtual machine mode on Linux is possible. I do that on my Ubuntu desktop. Allows me to run IE6 testing that otherwise I'd need another machine for.
Windows 7 pro users can download the vm image of Windows XP SP3 for free to run. Otherwise the 180 day time bombed images of Windows XP SP3 are freely down-loadable. The only downside to the latter is having to reinstall the windoz app every time.