When the city of Madera, Calif., needed a new voice system, it turned to open source technology -- not just for the IP telephony but for an entire network-infrastructure overhaul and loads of other functions. All the renovations cost less than half the estimated price of deploying a commercial VoIP system alone. This smart, budget-wise use of open source across the network wins the city a 2007 Enterprise All-Star Award.
http://www.networkworld.com/allstar/2007/112607-madera-open-source-voip.html