Wings is right. You should get an e-mail from the AMA with your membership number on it. (Or ask them to FAX you one.) Most clubs will accept that.

Glad you're going with a club; just be sure to get with an instructor as well. I've seen a few full scale pilots try to fly thinking, 'this should be easy, I fly the real ones', only to look really stunned when the plane is trashed ten seconds later.

It really IS a lot different than full scale.

Just be sure that you don't run the engine too lean. These little engines are pretty easy to tune, but a single lean run can ruin them. (It won't always, but it can.) The OS 40 FP, while an older engine (likely 5 or so years old minimum) is also a good, reliable engine. It should be relatively powerful and fairly easy to start. (I have 3 of them.)

Good luck and have fun!
Dennis-