http://walkscore.com/
perfect , google maps mashup and for a militant walker like myself quite interesting. density of tips in local neighborhoods is poor, but then I know whats available here anyway. interesting to compare west coast/ east coast, skandinavia, uk and japan.

http://walk2web.com
working on a project that is featured on t-mobiles web'n'walk the URL above peeked my interest. very web2.0, fun, inspiring and utterly useless.
try
http://walk2web.com/surf/http://moccabeans.com
to learn more about it