There are instant resonances between these and quilts and the previous mentioned article on Digital Crafts.
Online code generators can be found in many places. E.g. qrcode.kaywa.com
Since I heard of these codes, I have noticed them in so many places. I love the idea that there are secret messages all around me, just waiting to be decoded.
[aside: ... code readers can be downloaded for many digital camera phones, but there are several different standards for these codes and i have been, as yet, unable to find a universal code-reader for my phone]