qrd.by (GeoTagger for QR Codes)
Enter a location and URL and the service creates a QR code that embeds the geographically location
The Service includes an API for customising your QR codes
"You can optionally attach geo information to your URL. This may be your company address or any location where you want to stick your QR Code. The parameter
address is a human readable address string. The parameter lat (Latitude) and lng (Longitude) are used for further machine processing, e.g. to show the location on a map. The note parameter is used to add a detailed description about the location (e.g. 2nd floor, left door). You may add an image with the parameter image, that contains the path to the image." 
The http://qrd.by/hotspots provides a google map of geotagged QR codes that have been recently created and colours represent the number of times
Try it here
API details
