Netflix on iPhones: Now You Can Max Out Your AT&T Data Plan Almost Instantly!

The multiscreen dream is in full bloom at Netflix: The movie-rental service on Thursday launched its free app for iPhones and iPod touch devices — something that has been in the works for more than a year (see Next in Netflix’s Device Queue: iPhones and Netflix to Stream Videos to iPhone, Nintendo Wii: Source).

But will you watch a 2-hour movie on a screen that’s smaller than a postcard?

If you do, and you’re streaming it over AT&T’s network, make sure you’re on an unlimited-data plan.

The Netflix app is available via both Wi-Fi and AT&T’s 3G network, but note that AT&T now offers only usage-based data plans for smartphone users — which means you would hit the 3G usage cap for the entry-level 200 MB plan if you watched just 4 minutes of streaming video per day (see AT&T Bites the Bit-Metering Bullet and Cable Hearts iPhone’s Usage Caps).

AT&T’s own mobile “TV Everywhere” service is designed for download-and-go action: The telco’s app lets U-verse TV customers download shows over a Wi-Fi connection to an iPhone or iPod touch for later viewing (see AT&T iPhone App Lets U-verse TV Subs Take Some Shows To Go).

I do wonder how useful this will be given (a) the small iPhone screen size and (b) the limitations of the AT&T 3G network in terms of capacity and usage caps. (Netflix also offers an iPad app, which actually makes a little more sense given its larger screen.)

It seems, then, that the optimal place to use the Netflix iPhone streaming-video app is someplace that has public Wi-Fi. American Pie 2 at Starbucks, perhaps? Maybe.

Obviously, if you’re at home and you have a choice, you’re going to watch movies on the biggest screen possible, and at this point Netflix offers streaming of tens of thousands of TV episodes and movies to customers (on plans of $8.99 per month or higher) on more than a 100 devices.

Netflix is focused on building out a gigantic library of on-demand content as well as enhancing its user interfaces, as chief content officer Ted Sarandos told me in a recent interview (see Netflix’s Sarandos: Stream On).

By the way, the company no longer discloses how many titles are available for streaming but a Netflix spokesman says it’s “more than you can watch in a lifetime.”