I have been chipping away at building an Arduino based Weather Station. Upgraded to a Arduino Mega as I was running out of memory on the Uno with all the libraries and sensors I was using.
Have code reading the Anemometer/BMP180/TSL2561 at this point. (more code sharing in upcoming post).
Using basic Ethernet Shield at the moment for proof of concept. Will eventually go wireless.
Also have code writing to an Xively feed at: Weather Station
Will more than likely play with other sites like Thingspeak and or more Plot.ly.