Usefull Links
When you need a code without graphical integration
When the QR codes need to be read/scanned using a desktop PC.
Readers for Your mobile phone can be found in the various App stores.
I recommend the I-Nigma reader, it is available for multiple mobile platforms.
This reader and some other good mobile phone candidates can be found here:
Technical background about QR Codes
Nederland in bedrijf, Uw online bedrijven portal.
QR Media Guide, a Guide to all things QR Code!
PaperSpecs - Paper Information, Inspiration & Insights