Maryland-based FreedomPop, which promises free mobile broadband via an unusual business model, today announced the launch of its public beta program.  

FreedomPop users can sign up to receive 500MB of free WiMAX service, which is served up via a wholesale agreement with Clearwire's network. 

From there, customers can earn up to 1GB of data each month by adding friends to their network, or earn unlimited data each month by engaging in partner promotions. Users can also purchase additional data on a pay-as-you-go basis. 

Stephen Stokols, CEO of FreedomPop, said in a statement that the new service is aimed at delivering a "flexible alternative" to what he calls "expensive family plans" being offered by other carriers.   

FreedomPop will initially offer its service through two device options: the Freedom Spot (Photon), a hotspot that powers up to eight devices, and the Freedom Stick (Bolt), a USB dongle for laptops and PCs. 

The company also said it will begin shipping iPhone and iPod Freedom Sleeves, cellular-enabled cases, within the next four to six weeks.

In an interview with Wireless Week, Stokols said the beta period will last for the next few months and will "unthrottle" anywhere from the end of this year to the beginning of 2013.

FreedomPop has also secured a long-term agreement with Sprint, Stokol said, which will allow the company to offer a 3G plan on that network in the short-term, with an aim to also offer Sprint's LTE service in the future. 

Users can check the FreedomPop's website and enter their zip code and email address to find out whether the service is available in their area. The company said it is accepting users to the new service on a first-come, first-serve basis.