How to skip email verification after register and log you right in

I’d like to skip email verification, so I can allow my visitors log-in into the site (to download files) WITHOUT having to retrieve their password. (they could do it later)

I need them to register to the blog through wp registration, and not to login through an openID or other type of login, because I want to feature their gravatars in the site like a community.

I have e piece of code that logs you in right into the blog with the specified user acct. I think it can be fed with the just generated user and pass and putting it into the right place after the register process, it could work. But I don’t know where to put it (I’m looking for it right now!)

require('/home/content/xx/xxxxxx/html/wp-blog-header.php');
$user_login = 'generated_used_here';
$user = get_userdatabylogin($user_login);
$user_id = $user->ID;
wp_set_current_user($user_id, $user_login);
wp_set_auth_cookie($user_id);
do_action('wp_login', $user_login);

Help please!