Nice hack! Could you elaborate on why arduino + ethernet shield will be a better choice than raspberry pi + wifi? I'm genuinely curious because I've been looking at both for a hardware project and would love to know the advantages (and gotchas) of both approaches. :-)
Consider Electric Imp too - very small, very cheap, wifi built in, and the web connectivity is handled for you so you don't need to set up/secure/manage an http server.
I've got one that will control my electric desk from my phone, one day soon.
The Imp seems cool, but it's price point (when combined with the breakout board) is higher than a Raspberry Pi and Usb Wifi dongle. Not only is the price higher, the hardware isn't nearly as capable.
