This answer applies to jQuery version < 1.8
Best way to do that, probably the FireQuery plugin for FireFox. Really a neat tool.
If you want/need to accomplish that “in-code”, use jQuerys .data('events') object.
$.each($('#element').data('events'), function(i, e) {
console.log(i, e);
});
All events that were bound via jQuery gets pushed into that object. Of course, there might also be other event handlers like on-anything, for which you would have to check explicitly.
Ref.: FireQuery