Augme.com. Nice service that lets you generate barcode (either qrcode or datamatrix) for any mobile link. Once subscribe you can then generate your barcodes, tag them, search,… but I have not seen any statistic module.
Note that barcode generated move the targeted URL to augme.com domain. The URL encoded is hosted in another domain, format is the following: x.augme.com/somealphanumcode. Therefore when generating barcodes on augme.com you get tied to them.

I have been thinking about something similar with additional functionalities linked to the mobile world (transcoding service for instance) but I have not yet found the time to implement it…