I have just read and signed the online petition:

"Google Maps 'Bike There' Feature Request"

hosted on the web by PetitionOnline.com, the free online petition
service, at:

http://www.PetitionOnline.com/bikether/

I think it would be a cool addition to Google maps, perhaps you will
too. If you can spare a moment, please take a look, and consider
signing yourself. Seems to me that it would also give a person a good
idea about where to walk too.
Planning routes that assume you are in a vehicle can lead you astray,
but if a bike can use a route, than a pedestrian probably can too.