Ok, it’s not the usual thing to do but I think QR codes are great. You can read the rest of the post with your smartphone or scan the images online with this page: http://zxing.org/w/decode.jspx
If you’re interested in the technology then @ajaxlogos is a good place to start. He’s done a load of work on them and is being very creative.
I’m watching the #fiw11 stream on twitter and it sounds as though there are some great creative publishing ideas coming out.