<form id="tellastory" method="post" action="">
    <label for="fullname">Full Name </label>
    <input id="fullname" name="fullname" type="text" maxlength="255" value=""/> 
    <label for="title">Title </label>
    <input id="title" name="title" type="text" maxlength="255" value=""/>
    <label for="title">Message </label>
    <textarea id="editor" name="editor" rows="20" cols="50"></textarea>
    <input type="hidden" name="form_id" value="123456" />       
    <input id="saveForm" type="submit" name="submit" value="submit" />
</form>
<?php
$storyteller_user_id = "3";  //your guest user id here
//$stories_category = "3";  //your stories category id here
$key = "storyteller";

if ($_POST[\'form_id\']=="123456") {
    $my_post = array(); 
    $my_post[\'post_title\'] =$_POST[\'title\'];
    $my_post[\'post_content\'] = $_POST[\'editor\'];
    $my_post[\'post_status\'] = \'publish\';
    $my_post[\'post_author\'] = $storyteller_user_id;
    $my_post[\'post_category\'] = array($stories_category);
    $post_Num = wp_insert_post( $my_post );
    add_post_meta($post_Num, $key, $_POST[\'fullname\']);
}
?>