Update: Apple has reissued the update.
Apple TV software update version 4.4.1 is now available for download on the device. It can be obtained by navigating to "General," then "Settings," and choosing Update Software.
According to Apple, the software update addresses an issue that required a small number of Apple TV units to be connected to iTunes in order to complete last week's 4.4 update.
One of the major features added with last week's iOS 5 update is AirPlay mirroring, which allows a user to send their iPad 2 display wirelessly to the Apple TV. It also allows console-style gaming via supported titles like Real Racing 2 HD.
Last week's Apple TV update also added access to Apple's new iCloud-powered Photo Stream feature, which automatically uploads pictures taken with an iPhone or iPad 2 and shares them among iOS devices. With the update, users can view Photo Stream pictures on their HDTV.
The update also added access to iTunes Trailers, Wall Street Journal Live, and the ability to watch live games through the National Hockey League's GameCenter subscription service.