Originally Posted by Foon
Depends, your coach should be the one to do that. He'll tell you when you're ready. Mabye you should have a word with him about fighting, that should help.
I'm guessing the original poster doesn't have a coach yet, considering he's asking where to begin.
There are two ways you can go: 1.) you can find places that teach a striking art (there's many that are good [boxing, kickboxing, savate, muay thai, kyokushin karate etc.], pick one that suits you) and a place that teaches a grappling art (judo, Brazilian jiu-jitsu, Sambo, submission wrestling, etc.) and then go from there or you can 2.) find a gym that teaches MMA which will train you in both striking and grappling. What you learn there is what will do well in the ring.
Once you have trained for the 6 to 8 months (it would probably take longer than that to do well in a fight) then start talking with your teachers on where you can go to get into an amateur fight and they should be able to help you.