I have been following this guy on Twitter, Russel Tarr. He pumps out a lot of tweets about interesting tools, articles, and other items that teachers may find useful. Some of his stuff is hit or miss, but he cranks out tweets all day long. I find something everyday that is useful. One of his tweets today was about using QR codes. Here is the site to go to: http://www.classtools.net/QR/
This is a good example of what he puts out.