Harmonix has released a title update for Rock Band on the Xbox 360 that will make it possible to export 55 tracks from the original Rock Band disc for play in Rock Band 2.
Beginning today, September 4th, the title update will add an export disc tab under the extras option in the Rock Band menus, allowing owners of the original Rock Band to expand their Rock Band 2 library to include 55 tracks from the original Rock Band track list for the nominal fee of $4.99 (400 Microsoft Points). In addition, this patch is required for all future downloadable content releases for Rock Band. Previously purchased DLC will not be affected.
The selection of 55 exportable Rock Band tracks joins the weekly downloadable content list of over 200 songs to date and Rock Band 2's forthcoming setlist of over 100 songs  adding to the ever expanding Rock Band Music Library. By the end of 2008, Harmonix has promised an unprecedented 500 songs will be available for the Rock Band platform. For a complete list of Rock Band songs available for purchase and download to date, please go to www.rockband.com/dlc.