Making a username/password syncronization scheme - D7 I need to register my users to a 3rd party service upon registration in Drupal. I have toyed around a bit with hooks, and tried to catch the password upon registration so I can insert it into another database, but to no avail. The 3rd party DB encrypts the password in a different way, so I need to get the users password in clear text, crypt it and then save it to the database.

Can anyone give me some pointers to where I should look? hook_user_insert (&amp;$edit, $account, $category), both $edit and $account contains the users encrypted drupal passwords.
When a form is submitted, its values are validated by the functions listed in $form['#validate'] then processed by the functions in $form['#submit']. If there is no $form['#validate'], then the function FORM_NAME_validate will run (if any). Same for submit. 

See user_register_submit. The plain text password is in $form_state['values']['pass']. Write a hook_form_alter and add a new submit function to $form['#submit']. Declare that function and put the logic you need in it.