A form with
1. first name & last name
2. user_name [http://www.nixty.com/user_name]
3. email
4. password
Also, for #2 make sure people you display the corresponding url, so people know that it will be a part of their url as well.
Also, for #2 make sure people you display the corresponding url, so people know that it will be a part of their url as well.