Don't know if anyone has heard of this but I just got one and it's a really neat device. Most of you have probably heard of the Scangauge, this is a similar device but with a much smaller body and a better screen. If you're going to shop for something like this, do some more research on the differences.
http://www.ultra-gauge.com/ultragauge/index.htm
I paid like 65 bucks shipped and am using it mainly to monitor my instant and average MPG, as well as throttle position, fuel levels, etc. basically for fuel savings. It can give you a lot of other readouts on your car too, kind of like an accessport but without ability to adjust (but you can display 6 gauges per page and there are 7 pages available). In my 97 Civic it managed to pull up 41 of the 86 available readings. Neat tool, thought I'd share