If you want to create you own QR code then here is a simple Python script that will create PNG images for you.
First you need to install the Python Image Library and QR Code library. On my OS X system that was easy
$ pip install qrcode
Then you can create the following simple Pyton script.
#! /usr/bin/env python
It reads any text from it's standard input and writes a graphic image to the standard output. So you can do this
$ echo "My QR Text"|makeQR > myqr.png