I've published the beginnings of an open source home brew temperature controller for Arduino on GitHub.

My controller is based around an Arduino Uno clone from FreeTronics that includes a built in Ethernet shield.

I'm using an LCD & keypad shield for display and control, an 1-wire DS18B20 temperature sensor, and a couple of solid state relays to get the job done.

I'll be updating the blog and GitHub as I get closer to getting this working, though at the moment I have my first brew bubbling away at room temperature as I search for the right fridge to hack on the roadside.