Apple has quietly released its awaited Apple TV software upgrade that allows people to rent movies from Apple's iTunes online music store directly from their TVs.

For Apple TV owners, version 2.0 is installed automatically as the device, which streams video content from a Macintosh or PC to a digital television, periodically checks for upgrades. To receive the update, the Apple TV has to be connected to the Internet. A full explanation of the update process was posted Tuesday on the Apple TV support site.

Apple chief executive Steve Jobs said during his Macworld keynote last month that Apple TV 2 would be ready by the end of January. The company, however, delayed the release by a couple of weeks, saying it needed time to finish the upgrade.

The software update will allow people to rent movies from Apple's iTunes store using a remote control. Apple expects to have more than 1,000 movie titles available by the end of February, including more than 100 high-definition titles.

Apple's catalog represents only a tiny portion of the movie libraries of the six major studios that have agreed to make films available on iTunes. The studios include 20th Century Fox, Warner Bros., Walt Disney, Paramount, Universal, and Sony. New films will not be available on iTunes until 30 days after they ship to retailers on DVD. The delay is so the electronic release of a movie does not usurp sales for retailers, such as Wal-Mart, which account for the majority of DVD sales.

DVD-quality movies are available to rent on iTunes for $2.99 for older titles and $3.99 for new ones. High-definition versions cost a dollar more.