Currently, I'm working on a wiki on Augmented Reality in Education.
Check out the wiki for lots of interesting information. Shirley L turned me on to some great resources on the use of QR codes to trigger interactions.
Here's a bit from my wiki

To start creating a very basic application of simple augmentation, first download a QR Code Reader for your smart phone. For most iPhone users NeoReader works well For a list of readers for most smart phones see Mobile-Barcodes Once a reader is downloaded, access the application and point your smartphone camera at any QR code and you will be able to receive whatever information is triggered. To create a simple QR Code, there are a number of online generators. One simple generator is QR Code Kaywa At this site simply choose what kind of interaction you would like. You can trigger the code to send the viewer to any URL, send text, text message or trigger the users phone to make a phone call to a number. After you've done that, click to generate your QR Code.
To test that it works, just access your reader on your smart phone, point camera view and watch the action that is triggered. Once you are satisfied, you can print your QR Code and post it for others.

Now here is your task: Download one of the readers and point it at my QR Code in this post and see my favorite meme!