I bought an MPGuino, it's an open-sourced MPG gauge that'll make me enjoy driving my car less by reminding me how poorly I'm doing on fuel economy It can be seen here:
http://opengauge.org/mpguino/

It needs a signal from the VSS, an injector signal (the low,gnd,switched side?), as well as a constant 12V source.

Where is an ideal place to tap these signals. Electronics are really not my forte.

Thanks so much