Some of HBO's most popular programs will be available for sale on iTunes starting on Tuesday, consummating a long-gestating deal between the cable network and Apple, according to a source within HBO, which is owned by Time Warner.

HBO spokesmen Jeff Cusson would not confirm today's launch, but did say that the official announcement of the deal between HBO and Apple could come as early as today.

Some HBO shows will cost more than the content currently on iTunes, according to Cusson, though he would not disclose specific prices. He also declined to say which programs would be available first, but it is expected that some of the network's most popular series—including The Sopranos, Sex and the City, and Entourage—will be among the first.

Cusson said that HBO shows would not be available on iTunes until after the DVDs of the shows are released. That's a much longer delay than current shows on iTunes, many of which can be bought and downloaded one day after they are broadcast.

Not all of HBO's library will be available on iTunes. HBO and Apple have agreed on a "rolled-out release," which means that over time more and more content from HBO's libraries will be available.

Cusson also said that the idea that HBO pursued the deal with Apple as a result of pressure from parent company Time Warner is "absolutely ridiculous."

Apple representatives did not return calls for comment.