function isValidUrl($Url) {
        //check for an empty url first
        if (empty($Url)) { return false; }

        //let php tell us if it as a valid url
        $UrlElements = parse_url($Url);
        if( (empty($UrlElements)) or (!$UrlElements) ) { return false; }

        $scheme        = $UrlElements[scheme];
        $HostName    = $UrlElements[host];

       //check to make sure it has a scheme and hostname
       if(empty($scheme) or empty($HostName)) { return false; }

       //check the scheme (removes mailto and others)
       if (!eregi("^(ht|f)tp",$scheme)) { return false; }

       return true;
}