The guys at Dailyapps have figured out how to install Leopard on a PC, and it only takes three steps. They also list all the things you'll need to get this going. This isn't a supported configuration, obviously, so some things might not work. You're on your own if you want to run Leopard on a PC, but Apple is more than willing to sell you a Mac with Leopard pre-installed.
[via Laughing Squid]