1. you can set the the identity-column in the config file:
Code:
/**
* A database column which is used to
* login with.
**/
$config['identity'] = 'username';
After this you will have to make some changes in the controller and the view, so that the correct field is shown and validated.
2. The function logged_in() returns true if the user is logged in
The function is_admin() returns true if the user is an admin.
3. If you want to show the login form on every page, you can take the example code from the auth-controller, change it to your needs and put into a method which returns the form as a content string, which you can put anywhere you want to.
