Barometric Pressure Sensor to our Web Based Weather Station, and added calculations for Heat Index and Dew Point. You can read about how to build the Weather Server at http://www.instructables.com/id/The-Super-Simple-Arduino-Weather-Web-Server/ and I will be adding the new features to that Instructable.
I had to connect the sensor shield with jumper wires, as it did not play nice with my old Ethernet Shield. I will have to notch the Protoshield to avoid hitting the Ethernet Connector. The Ethernet Shield does not work stacked on top of the Protoshield, as it appears to use the ICSP Header.