obd2gpx takes obdgpslogger logfiles, and outputs gpx files. You can upload them to openstreetmap or similar, and they work fine.
This might help out with mp3car's crowdsourced mapping project, too
It's in the latest svn, the manpage is online here: obd2gpx manpage
OBDGPSLogger, for logging OBDII and/or GPS data
OBDSim, an OBDII/ELM327 software simulator
mp3car forums: obdgpslogger, obdsim