jQuery Form Validation plugin - works GREAT but not on SELECT menu

I’m using the standard jQuery form validation plugin and it works great on my form inputs but not the select menu. I’ve copied the code from the documentation examples exactly.

<script type="text/javascript" src="http://dev.jquery.com/view/trunk/plugins/validate/jquery.validate.js"></script>
<script  type="text/javascript">

        rules: {
            email: {
                required: true,
                email: true
        messages: {
            email: {
                required: "Enter a valid email address.",
                email: "Enter a valid email address."

<label for="heard_from">How did you hear about us? <span class="req">*</span></label> 
<select name="heard_from" id="heard_from" title="Please Select Something"   validate="required:true">
<option value="">-- Choose --</option>
<option value="search_engine">Search Engine</option>
<option value="friend_family">Friend or Family</option>
<option value="advertisement">Advertisement</option>

Has anyone experienced this problem