[jQuery] Newb question about accessing a form's inputs

[james]

Hi,

If I have a form:

<form name="myForm" method="post" action="myAction.php"
onsubmit="javascript:doStuff()">
    <input type="hidden" name="myHiddenInput"/>
    <input type="text" name="myNonHiddenText"/>
    <input type="submit" value="submit">
</form>

What is the equivalent JQuery syntax for the following?

function doStuff() {
        document.myForm.myHiddenInput.value = 'some dynamic var';
        return true;
}

Thanks in advance,
James