Wireless Sensor to Internet
I would use a Digi Xbee on the sensor to pass the information to a Connectport X2, which has either ethernet or wifi. The Xbee is a Zigbee radio with a simple serial interface. The X2 has a Zigbee radio and an IP connection and runs python.

There are several tutorials on how to get one working. This one looks like a good place to start.