Apple has updated a couple of knowledgebase articles on how to configure firewalls on both Macintosh and Windows systems to work with Apple TVs. People frequently post on the Apple discussion boards about not being able to see their Apple TV devices in iTunes, and in many instances this is from firewall settings not allowing the connection through. This primarily affects Windows and pre-Leopard users, since Leopard uses a digitally signed firewall exception for iTunes.
