You can assign your buttons a class and then reference with that.
<input type="submit" class="runthis" />
$(".runthis").click(function() { });
EDIT: this code works for me in IE6:
<!doctype html>
<html>
<head>
<script src="//ajax.googleapis.com/ajax/libs/jquery/1.4.4/jquery.min.js"></script>
<script type="text/javascript">
$(document).ready(function() {
$("input[type='submit']").click(function() {
alert("HI");
});
});
</script>
</head>
<body>
<form>
<input type="submit" />
</form>
</body>
</html>