I'm just a beginner (DEC 2007)in this project, I'm currently testing the beta version of Tripmaster on a Tomtom One XL (but it works with other Tomtom products). Tripmaster is a piece of software that abbles to save gpx files. For more information have a look there :
and there :
This beta 2V10 version is working much faster than 1.8a. The interval log is between 2 and 5 seconds wich abbles you to map downtowns. Of course you still have no precise mesurement under 10 meters but looks ok for me.
http://www.navit-project.org/ working with OSM
I did some tests with Navit : Those people have done a very good job. If you have linux try it ! (If you have problems to install it go to their IRC. irc server : irc.freenode.org channel : #navit
But first read the documentation.
For french people interested about Strasbourg please go there : http://wiki.openstreetmap.org/index.php/Strasbourg
Si vous voulez en savoir plus en français : c'est par ici http://www.openstreetmap.org/user/hermes_p