They’ve made it really easy to get a beta key for you to start playing Red Faction Guerrilla beta on Xbox Live.  Follow these instructions:

1. Goto fileplanet.com
2. Register your email(or login if you already have an account)
3. Click the Red Faction Guerrilla beta banner
4. Submit your information
5. A beta key will appear on your screen and also in your email inbox
6. Logon to Xbox Live
7. Click Redeem Code on the Marketplace Blade
8. Click Download and play!

Stumble it!