This information was provided by the LIVESTRONG folks for those attending the Austin event. It seems to be standard AA info and thus, is probably true for anybody flying with a bike. Since the subject has come up before here, I thought I'd post:

Bike Check (American Airlines)

If you are flying with your bike, please note that American Airlines allows you to bring a non-motorized touring or racing bike for an $80 special items fee. The handlebars must be fixed sideways and pedals removed - or pedals and handlebars must be enclosed in plastic foam or similar material. The maximum size and weight allowed are 70 lbs, 115 inches and acceptance is conditional on aircraft size and load conditions. If bicycle and container are less than 62 dimensional inches (H+W+D) and under 50 lbs., the bike is free in place of one 62 inch bag in the free allowance. If this item is in excess of the number of pieces allowed in the free baggage allowance, excess baggage charges apply in addition to the $80 special items fee.

Maybe this explains why some people haven't had to pay extra for their bikes -- it was counted as baggage?