According to the latest issue of Nintendo Power, you’ll need a lot of space handy if you plan to have DLC for Guitar Hero: World Tour for Wii.

Saving on SD cards is the way to go if you plan on downloading a lot of songs. The Wii system memory is then used as a “content cache.” This means you only need to have the free space for one song in the Wii system memory (about 200 blocks). … The game automatically transfers the song… plays the song, and deletes it when you’re done. … It all happens pretty quickly.