Do a search under "churning" or "credit cards" on the AA thread and you will find lots of info.

By the way, if you ask real nice Citi customer service may waive the annual fee or give you 5K miles or whatever (the offer can change from call to call) when you call to cancel. They will transfer you to the retention dept. on a cancellation call and the redemption folks are usually ready to deal. Just don't bite on the companion certificates or $50 off coupons which really aren't worth much.