What are the licensing restrictions/permissions for the free tracks in the Apple music libraries in say, Soundtrack and iMovie, GarageBand, and other bundled software? Does anyone know where to find documentation on this? I want to know if I can use one of these in a commercial project. Is there a licensing fee option? Or are they broadly considered free and unrestricted?

I'd also love to know more on this one. I read through the FCS2 books and found nothing on this issue that I recall.

Same here. I had a problem with a network not accepting a sound track I made. They didn't accept that SoundtrackPro tracks were license-free and I couldn't find any material about licensing. They made the client hire a musician who put together a 5 second zinger to replace the one I made. The funny thing is that about six months later I heard a promo on the same network clearly using a GarageBand track!

As far as i'm aware they're royalty free and usuable for commercial projects, but i can't point you to any documentation on it. I'm sure that's how they sell soundtrack pro etc on the promo videos etc...

EDIT: from apple's license agreement for soundtrack:

2. Permitted License Uses and Restrictions. This License allows you to install and use one copy of the Apple Software on a single computer at a time. You may use the Apple and third party audio loop content (”Audio Content”), contained in or otherwise included with the Apple Software, on a royalty-free basis, to create your own original soundtracks for your video and audio projects. You may broadcast and/or distribute your own soundtracks that were created using the Audio Content, however, individual audio loops may not be commercially or otherwise distributed on a standalone basis, nor may they be repackaged in whole or in part as audio samples, sound effects or music beds.

link: http://www.apple.com/legal/sla/soundtrack.html

So you can use it for whatever you want, you just can't resell the samples etc...

Here's a funny story about how far you can go with GarageBand loops:

http://iknowtheledge.com/random/ushers-love-in-this-club-made-with-garageband/

-Noah