MPGuino

the folks over at ecomodder.com have a nice little write up about using the atmega168 (thats the atmega8 with 16k of EEPROM) to drive a display and give you your speed and MPG. it specifically is targeted at older fuel injected cars where you just tap the injector signal, and the speed sensor, and your off and running.

It looks like a fun little project. i almost regret having a newer generation car where I fell pretty much obligated to reverse engineer OBD-II so I can read the fuel injector info directorly from the ECU. its so sad that is RIGHT THERE, but so hard to get to it!