http://www.remixfight.org/

LITERAL:
-What is Remix Fight?
Remix Fight is an online community that has bi-monthly remix competitions.
How do I enter a competition?
To enter, visit the upcoming fights page (http://www.remixfight.org/mt-archive/cat_loops.shtml) and download the loops provided there, make a remix using whatever means you have at your disposal (see remixing resources if you have none), and then e-mail it to entries@remixfight.org with your artist name, artist website (if you’ve got one), mix title, and a short blurb about your mix.
When making a remix, are we limited to the loops provided, or can we mix in loops from other sources (assuming no copyright problems)?
You can certainly use outside loops or sounds in a remix. Some fighters consider it a challenge and badge of honor to only use provided loops. Ethics aside, copyright problems are only a problem when someone complains. So if you have a cool idea that requires yanking something out of a commercial track, go for it. But be aware that if the hammer comes down, your song might be pulled from the website.
I want to submit a song to be remixed, what should I do?
First, you should be aware of the License we use for loops we receive and second you should read the information for Loop Artists. If you can abide by these restrictions then you should visit this forum (http://www.remixfight.org/phpBB2/viewforum.php?f=7) and suggest a few songs of yours that the community might be interested in. If there is a positive response to your material, you will be contacted by the current fightmaster about when and how to submit your loops.

Fuente: neural.it