AT&T, the nation’s only carrier of the Apple iPhone and iPad products, will be changing its data plan coverage to no longer offer unlimited data transfers.

Plans will now be sold with limited data and a premium price on higher data usage. The changes will not affect current customers in good standing with unlimited plans.

While the change could mean lower rates for those customers who mainly use their connected devices for email and simple Web browsing, it could also mean much higher fees for more data-intense users. Streaming videos, downloading content or heavy use of sites like Twitter and Facebook could end up costing those users more.

Nationally, networks are fighting to manage a data explosion as more and more of the Internet becomes available on smarter and smarter devices that access it. Other carriers may follow suit, with Verizon indicating it may instill similar plans on its network.

AT&T does plan to give users tools to track their data usage including real-time apps to watch their usage, text message alerts to warn of pending new charges if data usage keeps up, and so forth.

Some users are up in arms over the changes and industry analysts are interested in how customers will react to the new changes. There will undoubtedly be a backlash, especially from the heaviest users, but most think that the problems will smooth over time as users realize how much (or how little) data they were really using.