//**************************************
    //     
    // Name: Email Validator
    // Description:Email Validator check to 
    //     see if an email address is in the proper
    //     format or not.
    // By: Bhushan.
    //
    //This code is copyrighted and has    // limited warranties.Please see http://
    //     www.Planet-Source-Code.com/vb/scripts/Sh
    //     owCode.asp?txtCodeId=758&lngWId;=8    //for details.    //**************************************
    //     
    
    <?php
    function emailsyntax_is_valid($email) {
    list($local, $domain) = explode("@", $email);
    $pattern_local = '^([0-9a-z]*([-|_]?[0-9a-z]+)*)(([-|_]?)\.([-|_]?)[0-9a-z]*([-|_]?[0-9a-z]+)+)*([-|_]?)$';
    $pattern_domain = '^([0-9a-z]+([-]?[0-9a-z]+)*)(([-]?)\.([-]?)[0-9a-z]*([-]?[0-9a-z]+)+)*\.[a-z]{2,4}$';
    $match_local = eregi($pattern_local, $local);
    $match_domain = eregi($pattern_domain, $domain);
    if ($match_local && $match_domain) {
    return 1;
    } else {
    return 0;
    }
    }
    ?>
    Use the function like this :
    if (emailsyntax_is_valid($email)) {
    echo "Ok";
    } else {
    echo "Error";
    }