IMAC is probably one of the easiest competitive RC sports to get into. Get into a plane that tracks straight, rolls straight, and does a nice size loop that's round. This could be any of a hundred aerobatic mono or bi-planes on the market. Then, go to:

http://www.mini-iac.com

There you can lookup your region and find out when the next few contests are in your area. You do not have to join IMAC to participate, but you usually get $5 off the contest entry fee per contest. You can also download this year's Basic sequence and print yourself a call sheet. Study the sequence, learn the elements, and use a buddy to call them to you as you start practicing. Remember, in Basic Class, any plane goes, scale or otherwise. It's a fun class, and the competition is usually just some good-natured ribbing. If you can do a loop in front of you without flying over yourself, you can fly Basic. You do not have compulsory unknown sequences, nor is Free Style required. Despite your skill level, you should always start in Basic Class and feel your way up from there. You'll be amazed the pressures that you may experience as you step up to the pilot station for your first judged round. Basic allows you to feel out the contest scene and move in.

That's all there is to starting IMAC. You can dip your toes in for fun, or yell "Cannon Ball" and make a big splash. It's up to you.

Check out the web site and good luck!
Erich