AT&T confirmed today that it will slim down its text-messaging service plans, offering customers either unlimited messages for a flat monthly fee, or a pay-per-text service. The company is eliminating its middle-of-the-road option, a plan that allots customers 1,000 text messages for $10 monthly.

“The vast majority of our messaging customers prefer unlimited plans,” an AT&T spokesman said in a statement provided to Wired.com. “With text messaging growth stronger than ever, that number continues to climb among new customers.”

AT&T’s change in service, which was first reported by Engadget, will begin on Sunday. AT&T made a point to note that its existing customers aren’t required to make the switch if they’d rather stick with 1,000 monthly messages, the spokesman said, “even when changing handsets.”

Text messaging services are in a state of tumult, as a carrier-backed SMS (or short message service) is no longer the only texting option. Apps like Pinger provide free SMS to users through its ad-supported system. Facebook recently released its Messenger application, which allows users to send chat, text or e-mail messages to one another using the Facebook platform alone. RIM has offered its BlackBerry Messenger platform, which allows BlackBerry smartphone owners to trade text messages freely to one another using instant messaging protocols, skipping out on carrier fees. And Apple, of course, plans to introduce a similar service for iOS device users when iOS 5 launches later this year.

Still, the majority of the world’s mobile phones are still “dumbphones” — not BlackBerrys, not iPhones, and not smartphones that run Facebook’s app — so SMS isn’t going anywhere in the short term.

We’ve compiled a chart showing what other carriers are offering in the way of SMS. Check it out, and make sure you’re paying for the plan that works best for you.