In a debatably really dumb move, NBC has decided to stop selling its shows on iTunes. Apparently $1.99 a pop wasn't enough for them. Plus they claim to have concerns about piracy, yadda yadda yadda.
Seems to me having your shows up at iTunes for $1.99 is more likely to hedge against piracy than to cause it. Rumor has it they wanted an amount that would have driven the price up to $4.99/episode. Which is outrageous when you can get an entire season on DVD for $19.99 in some cases.
I hope they see their dumbness and change their minds, but we shall see. In the meantime, anything from NBC or SciFi won't be available for purchase anymore.