The iTunes Store has just begun selling shows from cable company HBO, starting off with episodes from six shows: The Wire, Flight of The Conchords, Rome, The Sopranos, Deadwood and Sex & The City.

Most shows sell for $1.99 an episode like episodes from other sources, but in a departure from the norm, iTunes is  instituting variable pricing on the HBO shows, asking a dollar extra for episodes of Rome, Deadwood and The Sopranos, which is a first for the US iTunes market.

Previously iTunes UK started selling NBC shows with variable pricing as well. Along with the HBO precedent, this is a sign that Apple might be selling NBC shows on iTunes once more, since the pricing issue was one of the bones of contention involved in the Apple-NBC split earlier.