Been following this for awhile. Basically, MS started this by patent trolling any Android OEM. Most caved and paid royalties, but two (Moto, B&N) refused and countersued. It's not just the Xbox 360 either. Moto is claiming patent infringement on Windows 7, Internet Explorer, Windows Media Player, and a few other things.
I'm rooting for Moto. Apple and MS need to stop with the mobile patent trolling.