QR or Quick Response codes were bought about as a way for "Big Manufacturing" to keep track of inventory. Today they are popping up everywhere. However, some don't know how they should be using them in their marketing. I have read very little about the "how" when it comes to being able to read one.
I have gotten a free app from the iPhone app store - Zappit. Once you have a "QR code reader" app installed on your smartphone - you are in business.
Have fun with them - you might be surprised what you find when scanning them. I have been :-)
I have also done a quick youtube video that was just uploaded having to do with this particular QR code to the left of this text. I walked through Zappit and also darkened the room so you could see what I was doing on my iPhone.
It does work. I always thought computers were going to catch on :-)