A great example of why not to do this is "Macarena." It was a huge song, but the guys who did the tracks only for paid $1500...and that mistake is costing them a ton of money, even today.
Go to www.amazon.com or www.musicbizbooks.com and get some books on music publishing. That will help you to make a good foundation for yourself and make sure you don't end up with the short end of the stick.