Andrew Miller’s link on Edutopia gives you a number of ideas for using QR codes within teaching practice.
As mobile learning becomes more and more prevalent, more effective ways are needed to leverage mobile tools in the classroom. Although the tool should be suitable for the task mobile learning can create both the tool and the need. Mobile learning tools when created with specific structures and aims can harness the excitement of technology with the purpose of effective instruction. Using QR codes for instruction is one example of this.
Why not see how you could integrate them within your lesson plans?