Hi folks,If you want to learn about GarageBand, here are 2 e-books which have been very helpful to me,
Take Control of Making Music with GarageBand '08 10 andTake Control of Recording with GarageBand '08 (1.0. They are in PDF and work quite well with Preview. Although, written for the sighted, you can relate to what the writer has written keeping Voiceover in mind.
They are $10 per book, but, if you buy them both, they are, $17.50. Find them here,
http://www.takecontrolbookscom/garageband-recording.html