US TV network NBC has made some of its primetime shows available via iTunes.

Law & Order, The Office, Surface, The Tonight Show with Jay Leno and Late Night with Conan O'Brien launched on the service this morning. NBC is also offering some shows from its cable channels (Battlestar Galactica from Sci-Fi and Monk from USA) and some from its archive - one series each from the 50s, 60s, 70s and 80s - including Alfred Hitchcock Presents, Dragnet, Adam-12 and Knight Rider.

All episodes cost $1.99 each.