Soundtrack Pro music rights

Apple’s royalty-free jingles and sound effects included with the iLife applications are all free to use, as clearly stated in section 2.C of the iLife Software License Agreement:

“You may use the Apple and third party audio 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 samples, sound sets, or audio content 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 files, sound effects or music beds.”

http://images.apple.com/legal/sla/docs/ilife09.pdf

You should this (also providing the above link) if you get into a dispute process with YouTube.

even for commerical product?

To be absolutely sure about that aspect I would recommend that you contact Apple's legal department for a definitive answer:

http://www.apple.com/legal