Well the first one is easy, simply put a line of code into your current site's form such as:
Code:
mysql_query("INSERT INTO myforum_user (username, password, email) VALUES ('$username', '$password', '$email')");
I'm not sure, but vBulletin might also require birthdate right away. As for the cookies, it shows what's being set in includes/functions_login.php with vbsetcookie(), and includes/functions.php contains vbsetcookie(), so you could try and work out the code from that.
- Jesse