jQuery('.submit').click(function(){
    var str = $("#ajaxForms").serialize();
    // If you realllly. want a parameter serialize, uncomment the following line
    // str += '&serialize=' + encodeURIComponent(str);
    str += '&action=myajax-submit';
    jQuery.post(MyAjax.ajaxurl, str,
        function(response) {
            alert('Got this from the server: ' + response);
        }
    });
    return false;
});