Using Firebug, FireQuery and this fiddle:

Hitting Cmd+Shift+C (Inspect Element) and clicking on the button reveals this:

Clicking on the events Object {click= } reveals this (after expanding some info)

And clicking on the function() reveals this:

Which should be the code you are looking for, right?

As a note, Firebug can't always find the exact line of code something came from. I've had this method fail completely! Another approach is to use named function expressions. Changing the code to:

$('#bigButton').click(function showMyLlama(){

  $('img#theLlama').show();

})

Now reveals this when inspecting the events object:

Which is way more useful than just function() as it is now obvious that this handler shows us a llama. You can also now search the code for the function name and find it!

Using Chrome, its built in web inspector and this fiddle:

Hitting Cmd+Shift+C (Inspect Element) and clicking on the button shows this:

Clicking on the button in the elements inspector then pressing Escape to open the JS Console:

In the Chrome Console, $0 refers to the selected element in the elements panel.

Typing in $._data( $0 ) will give us the jQuery (internal) data object which includes events, just like in our Firebug example, sadly, Chrome wont let us click on the function, but it will let us see the source:

<Broken Screenshot link>

A note about .live() events:

Live Events are stored on $._data( document, events ) and contain an origHandler that points at the function:

<Broken screenshot link>