I have a PostGIS database and I need to figure out a quick (in terms of setup) way of calculating the travel-time between points corresponding to geocoded addresses taking into account the route and speed-limits involved. It looks like the pgRouting extension combined with OSM data is going to be my best bet (although please correct me if there's a better alternative). Before I start going down that route, however, I was wondering if someone could just confirm whether or not I'm going to need any additional steps/data/software in order to do what I need? The points I have are within the US states of PA, NJ and DE.
In pgRouting the the shortest path function(s) return the route with the lowest cost between two points. If your
cost attribute is "time", then your shortest path will be the quickest route.
I recommend you to start with the pgRouting workshop, which explains about variable costs as well: http://workshop.pgrouting.org/chapters/advanced.html