Dave Peck's Software: Walk Score for iPhone
(Summer 2009)
Walk Score is a ground-breaking website that lets you get a walkability score for any address you type. The companion iPhone app lets real estate agents take Walk Score on the go.
Walk Score for iPhone is an Objective-C app using Cocoa Touch. Because it depends on MapKit, it is OS 3.0 only. I led the charge to build it along with @lincolnritter and @larubbio. An Android version is forthcoming.