Use of quearcode is fairly straightforward.

Enter a string to convert into the text box, and either 
press Enter or click Generate.  A png of the desired QR Code 
will open in your default image viewer, from which you 
should be able to save or manipulate it further.

You can also click Encode file..., and select a small file.
If it can be QR encoded, one will be generated.  If not, you will be
informed.

A set of sliders controls the error correction level, box size in pizels,
and border size in boxes.
