There's a whole market for "royalty-free music" (all of which costs money, but at least doesn't cost money per view) that exists entirely --- again, as I understand it --- because you can't just use random copyrighted songs in presentations, on websites, &c.
Sliderocket even links to some of these sites on an article about adding audio to presentations:
http://www.sliderocket.com/blog/2010/07/incredible-presentat...
Note conspicuous lack of "and if you like Apples In Stereo, just drag an MP3 into this window and make sure to say thank you in your presentation". :)
In any case, so I don't sound too much like a message-board-crazy, let me at least commend you on your taste in music. At least it wasn't Ke$ha.