NBC Universal and Apple Computer Inc. on Tuesday said they would make certain NBC television shows available for download on the iTunes music store.

The shows from NBC, the USA Network and the SciFi Channel span from the 1950s to the present, including “Law & Order,” “The Office,” “Late Night With Conan O’Brien,” “The Tonight Show With Jay Leno” and “Monk,” as well as older programs such as “Alfred Hitchcock Presents,” “Dragnet” and “Knight Rider.”

Customers can purchase and download the TV shows, including current programs the day after they air on TV, and watch them on their computer or iPod device. The NBC Universal programs will be available in newly designated areas of the iTunes Music Store featuring the NBC Universal brands, NBC said in a statement.

Most of the programs cost $1.99, the same as hit programs “Lost” and “Desperate Housewives,” which Walt Disney Co.’s ABC said it would offer at iTunes.

iTunes now offers more than 300 episodes of TV shows for viewing. Customers have purchased and downloaded more than 3 million videos since their debut on Oct. 12, Apple said in a statement.