I wrote recently about Mobile Device Economics and Security. The OpenBTS project could increase the rapid growth trend of wireless even more dramatically:

OpenBTS is an open-source Unix application that uses the Universal Software Radio Peripheral (USRP) to present a GSM air interface (“Um”) to standard GSM handset and uses the Asterisk software PBX to connect calls. The combination of the ubiquitous GSM air interface with VoIP backhaul could form the basis of a new type of cellular network that could be deployed and operated at substantially lower cost than existing technologies in greenfields in the developing world.

Naturally a question of managed spectrum comes to mind. Yet another explanation of why regulation is good for commerce can be found in an OpenBTS implementation on an unregulated island that ran into trouble finding air space.