Apple TV Synching Solution
Having trouble synching your Apple TV? I've had issues on and off and found a few tricks to get things going.
The most likely culprit is your router. I have an old D-Link router, and I have always had issues going through it. I put a switch between my Apple TV, Computer and the router and things worked much better. I went from synching working 10% of the time to 90% of the time.
If you can't, or won't replace your router then I have a trick that might help. I recently moved my TV and can no longer use my switch. Since I'm back to the D-Link again (over wireless this time) Synching has been horrible. However I've found the best way to get the Apple TV to sync (or show up in iTunes for that matter) is to select it as a Remote Speaker in iTunes. This will almost always initiates a sync and gets my "Shared" media to show up in iTunes again.