Here is a simple javascript redirect that uses the [Mobile Link Discovery Spec][1] a valid markup link tag that tells the browser where to find an Alternate for Hand-Held devices.
<link rel="alternate" media="handheld" href="http://m.google.com" />
simply replace m.google.com with the url of your mobile site.
and import this script
<script type="text/javascript" src="redirect.js"></script>