How can I programmatically delete a user?
This is not that hard, for D6 it would look like this:


Delete record from Drupal database users table;

user_delete(array(), $uid);

Change author on any content created by deleted user to Anonymous;

handled by the node module.
Send an email to our internal support address letting them know that the user should be removed from other non-connected systems

drupal_mail(...);


See hook_mail for details.