Apple has released a new version of GarageBand, which is a small update that fixes a number of small stability issues with the program. The focus of this update is to add support for opening projects that were created on GarageBand for iPad, and is a recommended update if you use GarageBand on both OS X and iOS devices. This update is for the OS X version of GarageBand, and not for iPads or other iOS devices.
The update is 47.44MB as a standalone updater and can be downloaded through Software Update for those who already have GarageBand installed, but can also be downloaded from the GarageBand 6.0.2 download page. The update requires you have OS X 10.6.3 or later installed.
Recently a number of GarageBand users were having troubles creating new guitar tracks, but there is no informaiton on whether this issue has been addressed in this update.
As always, be sure you at least have your relevant documents (GarageBand projects) backed up before applying this update, but preferably have a fully restorable backup of your system available.