O2 Wireless touts the new cards as a cost saving measure, enabling users to save money in "this difficult economy" since the plan also doesn't require long-term contracts.

The company, owned by Lotus Telecommunications, said that consumers can "ditch their expensive cell phone contracts" and purchase as much or as little airtime they want--recharge cards start at $10 for basic service.

To get the service though users need to have an unlocked GSM handset, or buy a new Alcatel 206 phone.

The Alcatel phone comes with fifty minutes of free airtime, which is also offered to new wireless contract sign-ups upon activation of service.

The service works with models from Nokia; Motorola; LG; Sony; Samsung; Palm; RIM; Pantech; and HTC, but does not support the iPhone. The GSM service is only available domestically--SIM cards will not operate outside the U.S. or U.S. territories.

To use the service, end-users need to buy a "Green Box" at a Best Buy Store or at BestBuy.com, activate service on the O2 Wireless nationwide network and insert the new Universal SIMCard into their existing unlocked GSM phone. The O2 Wireless deal is only available through Best Buy stores, Best Buy Mobile stores, Best Buy kiosks and online at BestBuy.com.

"The relationship with Best Buy is a very important partnership for O2 Wireless, and provides access to our simple, flexible, carrier-grade service, said Pete Grubb, vice president of sales and marketing at Locus, in a statement. "This service is well positioned for international travelers visiting the U.S., who are looking for a cost-effective way to stay in touch with family members back home."