I love these devices, which are appearing in advertisements and on product literature. Invented in Japan in 1994, they have only started to appear in the UK comparatively recently. On investigation, QR (Quick Response) codes can be used for a whole variety of clever tasks. As well as pointing to web pages, they can be used to store telephone numbers, SMS messages, event data, text, Google Maps locations, even the contents of a complete business card.
There are several free QR reader apps in iTunes and readers can be downloaded for most smartphones. Equally, there are several QR Code creator sites (many of them free) but we pay a small subscription at my favourite: QR Stuff.
A couple more sites with details of interesting applications for QR codes:
More useful info about QR Codes in the latest copy (September 2011) of Which magazine – http://blogs.which.co.uk/mobile/smartphones/what-are-qr-codes/