Yes, Nest is going to revolutionize, and jazz up the world of thermostats. But if you want something more legacy looking, and a bit more affordable and connected look at the Radio Thermostat Company of America (RTCOA) which has been around for 30 years. RTCOA offers three versions of “connected” thermostats: WiFi, Zigbee and ZWave. And to manage their designs/SKUs they have adopted USNAP. I believe leveraging USNAP was a fantastic idea – without introducing new models – the same model can accommodate support for multiple connectivity standards.
I have tried both the WiFi and Zigbee versions of the CT-30 model of their thermostat. The WiFi version appears to be powered by Marvell WiFi Controllers and RTCOA has made the APIs and discovery protocol available to developers. The discovery protocol uses Simple Service Discovery Protocol (SSDP). RTCOA makes apps available for IOS and Android.