AT&T is matching its competitors by opening up unlimited data to everyone.

AT&T has decided to throw up its proverbial hands after a week of intense competition in the mobile space, saying that as of February 17 its unlimited plan, which is currently only available to DirecTV customers, will be expanded to all postpaid customers.

Starting tomorrow, AT&T1 will launch a new AT&T Unlimited plan. The plan will be available to all consumer and business postpaid AT&T wireless customers.

The new AT&T Unlimited Plan will include unlimited talk, text and data on 4 lines for $180. Business customers can also take advantage of their additional corporate discount. You can also make unlimited calls from the U.S. to Canada and Mexico, and send unlimited texts to over 120 countries. Plus, customers on this plan can talk, text and use data in Canada and Mexico with no roaming charges when they add the Roam North America feature for no additional charge.

Prices remain unchanged — it's still $100 for the first line and $40 for the others, with a $40 monthly discount on the fourth after two billing cycles. That's considerably more than T-Mobile's and Sprint's options, but at $180 for four lines is right in line with Verizon, which AT&T considers its biggest competitor (though it shouldn't given how many postpaid customers it is losing to T-Mobile).

Unfortunately, unlike T-Mobile's most recent move, AT&T's unlimited plan includes its data-compressing Stream Saver feature, which lowers video quality to 480p by default. And there's no tethering, which is disappointing, especially when the other three big carriers include at least some tethering in their unlimited plans.

Are you switching to AT&T, or to this plan if you're already a customer, now that its unlimited plan is open to everyone? Let us know in the comments!

Which unlimited plan should you buy?