I was into (and still am, I just don't practice or train anymore, my knee is fucked up) Muay Thai fighting for around 2 years. Muay Thai is NOT an easy thing to learn or train for. If you did choose to learn the way of Muay Thai, be prepared for a world of hurt. The first few weeks to months of your training will probably be the worst in your life, due to all the body aches and pains you'll experience. Muay Thai can be extremely dangerous, I know of several guys who have shattered their knees, elbows, and fists during fights (scheduled, legal fights) and during training sessions. Muay Thai is more about attacks and strikes with your legs, rather than your fists, although you do use both, including elbows and knees.
Check out the following websites if you're interested in Muay Thai:
http://www.thaicollectible.com/history_of_Muay_Thai.htm
http://thaiboxings.genesis.mweb.co.th/page3.html
http://www.muaythaionline.net/
http://www.muaythai.com/