FrontlineSMS:Medic

Check this out: http://medic.frontlinesms.com/.
FrontlineSMS:Medic is a global health delivery project coming out of Stanford Medical School. A small group of medical students and undergraduates are leading this remarkable effort to leverage mobile phone networks in the developing world to achieve efficient healthcare delivery. Here’s the concept: mobile phones are distributed to community health workers who regularly travel to rural villages and administer care, while a single laptop running FrontlineSMS open source software is in communication with each phone to prioritize efforts. So if there is urgent need to administer to a pregnant mother in village A, a quick text can be sent to community health workers to prioritize their efforts there rather than having to wait till they make it back to the clinic, which can take several hours (even days) by which time it might be too late.
What makes this so cool is that they are utilizing an existing mobile signal network to establish a healthcare infrastructure. The concept is simple, the software is free, and it is all made possible by cell phone networks.