At about 5:40 in this clip, Stephen Colbert starts talking about the iPhone “kill switch.” This is when Apple iPod Touch and Apple iPhone regularly check-in with Apple servers to ensure that undesireable software is not installed. Watch it and find out how he knocks the Zune.
If you cannot hear the sound, try using Internet Explorer.
Good thing there is a simple work around to disable the kill switch: http://www.iphone-hacks.com/2008/08/12/iphone-2x-app-kill-switch-confirmed-by-apple-and-easy-workaround-already-published/