When the official announcement finally came last week that Rock Band 2 would release today on Xbox 360, one little bullet point on the press release about an additional 20 free DLC songs nagged us. Looking at the back of the Rock Band 2 manual now, we still have no idea what the DLC is, but we do know how we're going to get it. Going to the site listed in the image above currently gives this message: "Please check back in a few days for the opportunity to enter your Registration Code and sign up to receive the Bonus Downloadable Tracks." We've been told by Harmonix the tracks will release later this year.
Also, while we're on the subject, transferring the original Rock Band tracks to the sequel is really as simple as purchasing the license. No muss, no extra fuss.