If you've been experimenting with Arduino and Ethernet - but need to cut the cable and go wireless, you'll be in the market for a WiFi shield. However the cost of those can be somewhat off-putting, so an alternative needs to be found. One interesting and quite inexpensive hack has been documented by "Dirk" - who has hacked a really inexpensive TP-Link TL-WR702N to work with an existing Arduino Ethernet shield.
The little TP routers can generally be found for under $25, so with a little work you can remove the internals, connect them to your existing Arduino shield and the job's done. The router PCB is similar in size to an Arduino shield as well, so it can fit neatly on top, for example:
When putting together your next Internet-enabled Arduino project - save time, space and money with the Freetronics EtherTen. Apart from being fully Arduino Uno-compatible, it has onboard Ethernet, microSD socket, full USB interface (so you don't need a costly FTDI cable just to upload a sketch!) and supports optional Power-over-Ethernet.