In this example, we are going to hide the "title" field and populate it with the first and last name. We use CCK to add the firstname and lastname.
In this case we catch the "profile_node_form" but you catch any form you like.
<?php
/**************************************************************************
* Implementation of hook_nodeapi();
*/
function sns_form_alter(&$form, $form_state, $form_id){
if ($form_id = 'profile_node_form'){
$form['title']['#required'] = false;
$form['title']['#access'] = false;
};
}