Add additional fields to a Joomla 1.5 registration form

If you add new fields to the jos_users table, you need to modify the following:
libraries/joomla/database/table/user.php
libraries/joomla/user/user.php
com_user/views/user/tmpl/form.php
com_user/views/register/tmpl/default.php
com_users/views/user/tmpl/form.php
http://www.mysysadmintips.com/other/web/100
http://www.youtube.com/watch?v=qzf6ZKdjLZE