[jQuery] Getting the id of the next form

Hello folks,

I have a page containing a number of forms e.g.

<div id="alerts">
         <p><a href="#" class="ctrl_s">[an image]</a></p>
        <form id="f_alert">
                 [various form elements]
         </form>
</div>

<div id="whodidit">
         <p><a href="#" class="ctrl_s">[an image]</a></p>
        <form id="f_whodidit">
                 [various form elements]
         </form>
</div>

The class "ctrl_s" is bound to a function that will serialize the contents of the form and send the contents (via ajax) to the server for processing

$("a.ctrl_s").bind("click",function() {saveForm( [the id of the next form] );});

How do I get the "id of the next form" for sending to the "saveForm" function?   I'm afraid that I just don't yet understand selectors and traversing well enough to nut this out myself.

Thanks,

Bruce