the reg form

info

name = reg_form
description = "the reg form."
version = "6.x-1.0"
core = "6.x"
project = "reg_form"

install

<?php

/** 
  * Implementation of hook_install(). 
  */
function formfilter_install() {  
  // Set a high weight so the module is called after other modules that
  // modify forms.
  db_query("UPDATE {system} SET weight = -99 WHERE name = 'reg_form'");
}

module

<?php
function reg_form_form_alter(&$form, &$form_state, $form_id) {
  if ($form_id == "user_register") {
    //Look at the code in user_register_submit for all the ifs and switches to only
    // add this extra handler when a normal user signs up.
    $form['#submit'][] = "_reg_form_user_register_submit";
  }
}

function _reg_form_user_register_submit($form, &$form_state) {
  $form_state['redirect'] = $GET['q']; //Adds the current url as redirect.
}