Bicycle Directions on Google Maps
Google Maps has added bicycle directions, which take into account such things as bike trails and dedicated bike lanes (take when possible), as well as steep uphill slopes and busy thoroughfares (avoid!). It’s explained in some detail on the Official Google Blog and on Google LatLong. Matt points to this post listing the cities covered (all in the U.S. so far, alas). Rob Pegoraro runs its algorithms through their paces.