If you’d like to be able to stick your GarageBand installation somewhere else, the easiest solution is David Hodge’s free GarageBand Anywhere 5.0.1. This nifty utility can either move your existing GarageBand installation to another volume or, using the iLife ’05 installation disc, install GarageBand directly to another volume. You can also use the 'Fail-Safe Remove' to get rid of it completely & free up about 2.47GB. See the readme for more information.