GarageBand 1.1 addresses isolated performance and stability issues, allows per-track Echo settings similar to other effects, supports loop libraries in other disk locations, supports importing unprotected AAC audio files in addition to AIF and MP3 files, and addresses issues with ReWire support, moving GarageBand songs between different computers, Help support, fixing the timing of individual notes (as well as entire regions), and dragging entire tracks in the timeline.
Additionally, The update can be obtained by running Software Update from the Apple Menu. Enjoy!