I would look to drupal_redirect_form for answers...
http://api.drupal.org/api/function/drupal_redirect_form/6
for the lazy.   form_alter in a 'redirect' for user forms in a custom module...

On Wed, Nov 19, 2008 at 2:57 PM, Michael Favia <michael@favias.org> wrote:
Aldo Martinez Selleras wrote:
how can i do this! some module? any modification to user module
It basically boils down to changing the form action attribute to the appropriate value and handling the login credentials for the form submission. -mf