Is there a plugin/webservice to read QR codes

I want to generate/read the data to/from a QR code. I don't want to develop a QR generator/reader of my own.

Are there any plugins/webservice etc wh开发者_如何学编程ich I can use readily at my website??

I'm using PHP.

We have used this:

http://phpqrcode.sourceforge.net/

for a voucher system for a British newspaper. It works very well and has good documentation.