Would like to emulate google maps' driving directions functionality but use pgRouting instead. google's data over the project area & scale is quite a bit off so we want to use our own transport network data in postGIS.
Check out the OpenGraphRouter project.
Stephen Woodbridge has created a demo demonstrating the driving directions.
There is a pretty good thread on the PostGIS-users list related to this.
I've never used pgrouting myself (should have, actually) but http://twitter.com/pgrouting seems to be a good source for latest information about the project and users.
For setting up pgrouting and visualising it with Udig http://www.utdallas.edu/~ama054000/rt_tutorial.html
Make sure your using the right SRID, common ones: 4326 - WGS 84 Long Lat, 4269 - NAD 83 Long Lat, 3395 - WGS 84 World Mercator, 2163 - US National Atlas Equal Area
Here is a good example of pgrouting in action with Open Street Map (Cloudmade 'Web Lite') Data
route: http://www.ridethecity.com/nyc?rid=866162 (icon markers are draggable and re-calculates route)