We're always fans of a good Arduino project. While a few Wi-Fi solutions have existed to connect your Arduino to the internet wirelessly, the release of the new Arduino Wi-Fi shield makes those projects even simpler.
What's nice about the Arduino Wi-Fi shield is that it's incredibly simple to use and set up. As is always the case with Arduino, everything is open sourced, and the reference materials make it easy to learn how to use. The Wi-Fi shield snaps on to an Arduino, connects over 802.11b/g networks, and features both WEB and WPA2 encryption. From a physical standpoint, all you have to do is connect the shield to your Arduino and you're good to go.
Arduino Wi-Fi Shield [Arduino Store]