Originally Posted by
Boyd Reynolds
Google maps does have bike routes but you have to do a little extra clicking to see them. On the google maps page click "get directions" at the top left, then click the bike icon in the list of 4 icons, then enter some local addresses in the boxes that appear. You will see a map with a suggested route and all the bike lanes, paths, and routes marked. The suggested route isn't likely to be the very best route for you, but with the map you can work out what you want to try. It's a nice tool.
+1... or click on the more button between the Map and Traffic (if there is one in your area) buttons. This brings up additional map layers you can add, including a check box for "Bicycling"
ridewithgps.com is my other go-to site for mapping routes.
Also of note is that the latest Google Earth has an elevation profile tool for a given path/route. I don't think there's a bike lanes/bike trails overlay for Google Earth yet, though.