There are many websites that you can go to in order to create your own QR codes. The one I use is:
http://www.qrstuff.com/ You can embed text or an URL. In the above example, the QR code takes my class of 6 year olds to a child friendly website on the Monarch butterfly.
Below is an example of how I make websites we use regularly easy for my students to access on their ipads, by using QR codes on the walls of my classroom.
Here I have used a QR code to enable students to follow up a reading lesson on Shipwrecks. The website is about the Titanic which they took a particular interest in when reading. I found this was also a good way of extending my more able students.