via adafruit industries blog.

Tweet-a-Watt kits are now available! A few months ago, using “off-the-shelf hardware”, we modified a Kill-a-Watt(TM) power meter to “tweet” (publish wirelessly) the daily KWH consumed to the user’s Twitter account (Cumulative Killowatt-hours). We released this project as an “Open source hardware” project – in other words, anyone can make these, modify them and make a commercial product from the ideas and methods.

After we released this project we entered it in the Greener Gadgets design contest and won first place, we donate the winnings to “Engineers without borders“.

You can see the “Tweetawatt” account on twitter here!