Amazon.com has started selling movies and television programs that can be downloaded and watched only on a computer and portable video player.

The long-expected service, dubbed AmazonUnbox, is the first major download effort by the largest online retailer, though it has in the past hinted at a music download service, reports the New York Times. The new service will compete with Apple's iTunes, which offers TV shows and music videos, and other video retailers, such as Google, AOL, Movielink and CinemaNow. Apple is expected to announce next week that it will also sell movies.

The new service will sell most movies for $7.99 to $14.99 and most television programs for $1.99. Users can also rent movies for a 24-hour period for $3.99. All current and back titles of all major movie studios, except Disney, are available. It is also the first to license the original "Star Trek" series.

Amazon is not allowing users to burn DVDs of the downloads - likely in response to studios' demands. Because the quality of downloads is high, downloads will take longer than usual: 2-7 hours.