Or, to rephrase the question, "I know how to add event handlers to an object -- how do I enumerate what's already been attached?"
And it's pretty easy, but unfortunately it doesn't use a public API. Anyway, try this in Firebug:
If there are any events on that element, they'll be displayed. The only drawback is...you have to know exactly which element the events are attached to, or guess around a bit.