Two of the major players in the US entertainment market have joined the rush towards online TV programming.

Fox has started selling its programmes on Apple's iTunes system in the US for $1.99 an episode. The content includes hit shows such as 24, Buffy the Vampire Slayer, Prison Break and The Shield. 

The deal also covers content from cable channels FX, Speed, Fuel and the 20th Century Fox Television Library.

Eddy Cue, vice president of iTunes at Apple, said that he is "thrilled" that the Fox content is available on iTunes.

Meanwhile, Warner has surprised everyone by announcing plans to sell its content using the BitTorrent file-sharing service. 

BitTorrent is usually associated with illegal downloads of movies, television and music. However, Warner said that it is planning to sell legal downloads on the same day that a DVD comes out for sale.

The service is intended to launch in the summer and will initially feature more than 200 Warner Bros new releases, catalogue favourites and television series.

Ashwin Navin, president and co-founder of BitTorrent, told the Wall Street Journal that the downloads could be as cheap as $1 to tempt users. "We are working with a user base that is accustomed to not paying for content," he said.

However, the films could be locked to the computer on which they are or iginally downloaded and will not play on any other machines.

"The technology behind BitTorrent is elegantly designed for the delivery of large files like TV programmes and films," said Darcy Antonellis, executive vice president of distribution technology and operations at Warner Bros Home Entertainment Group.

"Our company was established to provide innovative, next-generation distribution models, and this relationship provides us with a unique platform to reach a new set of movie fans."