The OpenTracker project now has kits! –
The OpenTracker is an APRS unit that transmits data via amateur radio Packet. Usually the OpenTracker is connected to the microphone input of a radio (generally a 2-meter handheld or mobile.) Data from a GPS receiver gets encoded and transmitted in APRS format, and in many parts of the world there’s an extensive digipeater and gateway network that’ll get the data onto the Internet. From there you can access it through websites like OpenAPRS, APRS World and Findu.com.
It has onboard temperature and voltage sensors, and it’ll also connect to a number of different weather stations, including the 1-Wire weather instrument from AAG.
The OpenTracker is a transmit-only device. It can’t receive or decode any data itself. If you’re using the APRS network and you’ve got Internet access, you don’t even need to decode anything off the air – IGate stations will do that for you. For other applications, the simplest way to start receiving data is to install a soundcard modem program like AGWPE, and simply connect a scanner or radio to your computer’s audio input.
OpenTracker project – Link.