Apple updated GarageBand '09 to version 5.0.2 Monday. The update includes the usual "overall stability" improvements and fixes for "other minor issues." It also includes improvements in the purchasing process for Artist Lessons in the GarageBand Lesson Store, and some issues with browsing Jam Packs in the loop browser.
The patch is a 108MB download through Software Update if you have GarageBand '09 or iLife '09 installed.