ROADS (and other transport networks)

Looking for transport data? thinking of collecting roads data? wondering how to use it in innovative and useful ways? want to suggest new and improved methods?

post your questions and comments here.

some sites to get you started:
UNSDI-T: www.unjlc.org/mapcenter/unsdi
OSM: www.openstreetmap.org
gROADS: www.groads.org