I didn’t actually think about this when I “rediscovered” OpenStreetMap the other day and wrote my blog post about it; there’s yet another feature that OpenStreetMap doesn’t offer… routing! I didn’t really notice that as I’m hardly using this feature on Live Maps or Google Maps, but in fact, there’s no from-to route finding service on OSM.
BUT luckily there is OpenRouteService, a free routing service that is based on (as you may guess) OpenStreetMap. Another great example of what to do with a free worldwide street database 
Here is a summary of the online routing services that are available using OpenStreetMap data:
http://wiki.openstreetmap.org/wiki/Routing/OnlineRouters
Thanxx for sharing that link. It provides a good overview of free routing services and an update / addition to my post above.