Well, some, Android phones. Specifically the HTC Incredible, Nexus One, Evo 4G, G2, and the Samsung Nexus S. More phones will gain access to the Netflix app down the road, Netflix HQ promises.
One cool functionality the Netflix app implements is the ability to start watching something on your phone, then resume watching it on your TV or computer later. Start watching an episode of Battlestar Galactica, pause, go to the bathroom, watch some more on your phone, pause, flush, [EDIT: wash hands], and resume watching back on the TV.
What other use is that for, if not for that purpose?
Check out the app in the Android Marketplace today!