Today I wrote a blog entry about QR codes in our eKiwi.de blog. There we where using an online tool to create the QR code.
If you want to create QR codes dynamically on your website, you can use the class from http://phpqrcode.sourceforge.net/
The usage is pretty simple. In this example I created an image php file:
This outputs date and time into a QR code and outputs a PNG file. In the HTML file we only have to show the image:
<img src="img.php">
The QR code looks like that (if you do a refresh in the browser the code will change):
And that’s it. 
More documentation can be found on the projects homepage.
Here is the complete example as download.
