What a QR code is, is a scanable code that contains text, usually a website address, that is what mine will be, it will be my website address. they are similar to a bar code, but two dimentional, so they hold about 100 times the data.
I am using the service from http://www.qrstuff.com/
Basically, you just put the text into their textbox, and then you can download the code.
I can use this code for things like business cards.
You can also do codes for contact information, that might be more of the type of code for putting on the back of a business card.
Here are my two QR Codes. The one on the left is the website its self, the one on the right is my contact information.