Today I got a message on my Apple TV (the new 2nd generation one) that there was a software update available. So I initiated the update. It downloaded fine then progressed to the screen with just the apple logo and the progress bar below it. Under that it says:
"Step 1 of 2: Preparing update... Do not unplug your Apple TV while it updates."
And that's where it has been stuck for about an hour. The progress bar hasn't moved past the first little bit.