After I got my AppleTV 2, I had ongoing issues getting it to see my Mac's in the house. I tried rebooting, turning on and off Home Sharing, rebooting the AppleTV and it seemed really random when it would work or not work. This was very frustrating since I'm used to things "just working" when it comes to file sharing, iTunes sharing, etc.
Then, last night I was trying to get it setup and working and when faced with the same issue I started digging around my Network Settings and changed "Configure IPv6" from "Off" to "Automatically" and like magic, instantly my iTunes Home Sharing showed up on the Apple TV.
I know many have had this issue and while it may not be the fix for everyone, it fixed my problems.
Then, last night I was trying to get it setup and working and when faced with the same issue I started digging around my Network Settings and changed "Configure IPv6" from "Off" to "Automatically" and like magic, instantly my iTunes Home Sharing showed up on the Apple TV.
I know many have had this issue and while it may not be the fix for everyone, it fixed my problems.
Maybe you would want to move this to the HowTo thread, just a thought on your cool hint.