You will first need pick up the Sixaxis Controller app for $1.74 over at the Android Market, and make sure that your XOOM is already rooted before it can work. Of course, there is the option to hook up the PS3 controller to your tablet via USB, so that you can enjoy the standard controller experience for games on the Android platform. Surely games like Angry Birds are not meant to work with such a controller, as those fare far better with your finger.
When rooted, you are able to hook up to a quartet of Sixaxis controllers simultaneously. Anyone wants to relive the golden age of their childhood with NES and SNES emulated games using a modern day controller?