You really should use a descriptive title instead of someone's name.
1. That depends on where you are listing them. Is the code already available to grab $username? You aren't giving enough information (and proper xhtml is <br />, not <br>)
2. Probably a loop to go through the ids and then get the username. You can probably find the code to do that in the member.php page for the Friends tab or in the profile.php page for the Friends/Contacts list there.