Currently App of the Week in iTunes[UK], myTour is an app that allows users to create their own guided tours. Users can create a tour via the site and afterwards is provided with QR Code posters as a PDF they can put up at the various points of interest along the tour. Nice idea.
The app and tour creation is currently free. Go to mypersonaltour.com for more details and create a tour of your own.
Might be wise to check with you local authority before you go plastering up posters, just to be on the safe side.