The iPhone is now available at 5 additional U.S. regional wireless carriers, meaning users of Ivel, Kentucky-based Appalachian Wireless can get a hold of a 4S model for $50 less than AT&T customers. With the 3 largest mobile providers in the U.S., Verizon Wireless (108.7 million), AT&T Mobility (103.2 million) and Sprint Nextel (55 million), comprising the lion’s share of iPhone sales, the small, regional outfits aren’t as often mentioned.

As of last week, Alaska Communications, Cellom, MTA Solutions, GCI and Appalachian Wireless all carry the iPhone 4S, and are selling the iPhone 4 for $99. Here’s a rundown of some of the plans:

Appalachian Wireless –

Alaska Communications –

The rural services are also cheaper – both Alaska Communications and Appalachian Wireless’ voice and text plans with 5 GB of data are roughly $30 less that what AT&T charges, though it would be interesting to find out first hand how reliable their networks are.

In related news, it has just been speculated that Apple’s iPhone 5 model will feature an In-Cell touchscreen, which would make the device thinner and lighter.