The latest wireless operator to land the iPhone isn't T-Mobile USA or U.S. Cellular. It's nTelos Wireless, a regional carrier with less than half a million customers.

The company announced today it would begin selling the iPhone 4S and iPhone 4 on April 20, when it plans to open stores early at 7 a.m. EST for customers who want to get their hands on the device.

NTelos is the second regional operator to get the iPhone after C Spire Wireless began selling the device last November.

Apple's apparent decision to open the iPhone to smaller operators has been something of a victory for regional carriers, which have argued that exclusivity agreements like AT&T's four-year grip on the iPhone forced their customers to choose between high-profile smartphones and their preferred provider.

Jim Hyde, president and CEO of nTelos, said the company was "pleased" to be able to offer the iPhone to its customers.

"[The] iPhone 4S offers an abundance of new features, and with our industry-leading, nationwide smartphone plans, customers can now enjoy the nation’s best networks for less," he said.

The company is selling the iPhone at a $50 discount from its larger competitors. The 16 GB model of the iPhone 4S sells for $150, the 32 GB model goes for $250 and the 64 GB model runs at $350. The iPhone 4 will retail at the cut-rate price of $50.

Customers must sign a new two-year contract and sign up for a smartphone plan – they begin at $80 per month and include unlimited data and messaging.

Financial details of the agreement between nTelos and Apple were not disclosed. Sprint is paying $15.5 billion for the privilege of selling the device, but its sales volumes are expected to dwarf those of a carrier the size of nTelos.

Getting the iPhone onto shelves at regional wireless providers has been a goal of the Rural Cellular Association (RCA). Steve Berry, RCA's president and CEO, said at a conference last week that the trade association has "tried for a long time to get Apple engaged with our members."

If nTelos' iPhone announcement is any indication, those efforts may be paying off. At the same event, Atlantic Tele-Network President and CEO Michael Prior said the iPhone "will continue to make its way through [the RCA's] membership."

NTelos had 414,500 customers at the end of last year. It provides wireless service in Virginia, West Virginia, North Carolina, Pennsylvania, Ohio, Kentucky and portions of Maryland. It also has a roaming agreement with Sprint to provide wholesale access to its CDMA EVDO network in some of its markets through mid-2015.