Green WiFi and Mesh WiFi
Green Wifi "seeks to bridge the last mile internet access with nothing more than a single broadband internet connection, rooftops and the sun".
Mesh WiFi is a network technology and topology in which each user is also an wireless access point, moving signals to and from neighboring users to create a wireless network (the 'mesh') without a separate wireless infrastructure.
Mesh WiFi has value in emergency response: this podcast talks about how "mesh WiFi" was quickly deployed after Katernia. IEEE Spectrum Radio (Select the "October 2006" podcast, then skip to its second track.)
For developing countries, solar WiFi and mesh WiFi converge in products like OLPC's XO laptop. The unit has the ability to act as a mesh point when laptop's main CPU is off. (The XO can be charged via a crank, pedal, pull-cord or directly connected solar panel, but does not have integrated solar.)