Q: What about registered music or registered movies (i.e. songs by Pearl Jam or movies like 300)?
A: NO. NO. NO. If you are using a royalty-based or a registered song, you MAY NOT USE IT UNDER ANY CIRCUMSTANCES unless you have SIGNED PERMISSION with NOTARIZATION that you can use it to be distributed. That includes commercial games and non-commercial.
WHY? That could take forever. Basically, as of late, the RIAA and the MPAA have been suing like crazy for damages against people who have their works on P2P sites and who download/distrubute MP3's of them illegally.
How can they? Well, they claim that sound and video is the sole method of distributing their property and if they can't control that they can't control anything.
This seems fishy and it is, but judges have backed them up. They have a lot more money than you and can "define their case" better with said money.
JUST DON'T DO IT.
If the music/videos are non-registered (i.e. songs for free on Download.com or a video of your dog on YouTube), then you may distribute like crazy. Just don't forget to credit or else they can take measures toward stopping the distribution.