Verizon Wireless has expanded tests of its unlimited mobile-to-mobile calling plans to Arkansas, Oklahoma, Mississippi and West Tennessee, most cities in Texas and areas of Florida and Alabama.

The carrier’s experimental Unlimited Any Mobile plan offers unlimited calling to any mobile telephone number in the United States regardless of service provider. Subscribers have until the end of the year to sign up for the plans, which became available yesterday.

“Our top priority is providing a plan that meets our customers’ needs,” said Steven R. Smith, region president for Verizon Wireless, in a statement.

Single line plans under the pilot program include a $59.99 monthly plan for 450 minutes and a $79.99 monthly plan for 900 minutes. The program also includes family plans ranging from $99.99 for 700 minutes to $129.99 for 2,000 minutes.

The plans compete with Sprint’s all-you-can eat data plans with unlimited mobile-to-mobile calling, which include a $69.99 per month for 450 minutes plan and a $89.99 monthly plan for 900 minutes. Unlimited service plans for voice and data are a key part of Sprint’s business strategy as it works to compete against Verizon Wireless and AT&T.