There’s a good chance you haven’t yet unlocked or perfected all of the 85 songs already featured in Rock Band 2, but just in case you need more, Harmonix and MTV have flung wide the gates on how you can get your hand on 20 more free downloadable songs.

If you’ve taken a close look at the back of your Rock Band 2 manual, hard to notice in the midst of all your rocking, you’ll see a website and a code which you are told to enter in order to access the free DLC. The website is now live, so you can head on over and input your code and email address and the free music is yours... in a manner of speaking.

You see, the songs aren’t technically available yet, so rather than instantly receiving your Xbox Live redeem code you’ll get a request to confirm your email, which means that when the songs do become available, Harmonix will send you a notice with your redemption number. Think of it as picking up your tickets at the Will Call window. The website says the tracks will be ready "in a few weeks," so we’re guessing that Harmonix is planning on debuting the DLC across all three consoles simultaneously, so we’ll likely be waiting on the PlayStation 3 and Wii launch before the new music appears.

So anybody want to take a stab at what these new songs will be? All we know so far is that they aren’t going to be songs from the first Rock Band, but beyond that it’s shrouded in mystery. Is this going to be a mega-pack of one band? A sampling of the greats? A collection of indie bands few folks know about? None of that matters of course because it’s 20 free songs, which is more than you’ll be getting in next year’s AC/DC expansion, and $40 cheaper than that game’s retail price.