If you already have a RockBand.com account: sign into your RB.com account. Click on My Gameplay>Settings (both of these are in the left-hand bar of the website). Under the "Social Network" tab you'll see a giant "Connect with Facebook" button. Click on that and follow the on-screen directions. Once your accounts are connected, you can quickly and easily log in on the main RockBand.com account page by clicking "Login with Facebook."