I was alerted to a neat site today by the Bike Riding Donut Guy. It's called Walk Score (recently acquired by Redfin, new link is now active here), and the idea is that you put in your address and it tells you where all the key facilities available to you in walking distance. It also gives you a score based on 100 to let you know just how conducive your area is to walking based on the stuff nearby. My home in Clintonville had a 66 out of 100 - not bad, but it could be better.
It doesn't appear to take into account things like the presence of sidewalks, it seems, or safe routes to walk... just locations of key services.
Obviously, it's for walking, but it can certainly be used for biking, too. Check it out.