Which AP's have you got? I'm using the Cisco lightweight AP's and as they have no real smart, you can't do much monitoring on them. However when you look at the controller, you can get some stats on how many clients are attached to the AP's, history of the clients etc.
But what you could do is monitoring the interface where the AP is plugged into. You could then lower the speed settings so that it will show as maxed out or what ever you're looking for. I do this as well so I have an overview of all the AP's in one place and can quickly see if one is doing lots of work.