Apple today announced that all four of the major networks are offering primetime programs in high definition on the iTunes Store.

Apple still provides no ad-supported streaming offering, which has opened the door for Hulu and others to target the huge audience for free streaming Internet television.

The list of HD programs now available on the iTunes Store includes ABC’s “Brothers & Sisters,” “Desperate Housewives,” “Dirty Sexy Money,” “Eli Stone,” “Grey’s Anatomy,” “Life on Mars,” “Lost,” “Private Practice,” “Samantha Who?” and “Ugly Betty.” CBS programming includes “CSI,” “CSI: Miami,” “CSI: New York,” “NCIS” and “Numb3rs.” FOX shows include “Bones,” “House,” “Prison Break” and “Sons of Anarchy,” which airs on FX. NBC shows include “30 Rock,” “Heroes,” “Kath & Kim,” “Knight Rider,” “Law & Order: SVU,” “Life,” “Lipstick Jungle,” “My Own Worst Enemy” and “The Office,” and SCI FI Channel’s “Battlestar Galactica” and “Eureka,” and USA Network’s “In Plain Sight,” “Monk,” “Psych” and “The Starter Wife.”

Standard definition television shows on the iTunes Store are $1.99 per episode, while HD programs from ABC, NBC, CBS and FOX are $2.99 per episode. Many series offer a season pass option which allows customers to purchase entire seasons at a discounted price.

“We’ve got an incredible Fall 2008 TV lineup with over 70 primetime comedies and dramas, including many of the most popular shows on TV in stunning HD,” said Eddy Cue, Apple’s vice president of Internet Services. “With over 200 million episodes sold, iTunes customers have proven they love watching television on their computer, iPod, iPhone and TV with Apple TV.”