install custom songs as DLC onto an SD card, to be played in Rock Band 2 (&more)
For you rockers, i have found this in Wiibrew.org:
Official site : RawkSD
RawkSD allows you to install custom songs as DLC onto an SD card, to be played in Rock Band 2. It also allows importing songs from Rock Band 1 and all Guitar Hero games.
* Easy to use PC and Wii installers for customizing Rock Band 2
* Supports custom songs made for Rock Band and Guitar Hero games
* Allows you to play any song from Rock Band and Guitar Hero game discs in Rock Band 2 (15 games in all!)
Installation and usage instructions can be found on the RawkSD Wiki.
* Fixed MIDI saving bug with Guitar Hero 5, World Tour, Metallica, and Smash Hits
* Imported drum chart is Expert rather than Expert+
* Guitar Hero 5, World Tour, Metallica, and Smash Hits support added
* RawkSD Patcher has been updated to support ripping from Playstation 2 discs
* Complete fixes made for custom charts on all difficulties
o It's suggested that you use the Replace Files feature to re-import all your custom audio and charts
* More tagging info done (thanks again to tw3nz0r and BHK)
* The Wii RawkSD Installer has been totally revamped
o No more need for the PC during installs.
o Added integrated disc ripping support to SD and USB
o New option to backup and restore your savegame
* Previews now fade in
* Previews are louder and fixed for RB1-engine imports
* Guitar Hero 1 (and 2, 80s) are importable (ark files must be read off of a PS2 disc)
* Better tagging info for all importable discs
* More miscellaneous fixes for custom charts
* The Wii RawkSD Installer installs much faster than before
* Special language characters with accents no longer show up as '?'
wiibrew link: RawkSD - WiiBrew