Drupal-url2qr is a project mainly written in ..., it's free.
Generates a QR-code from the current URL and displays it in a block.
h1. URL2QR
Creates a QR-code from the current URL and displays it in a block.
Configure block to change title, image alt text and add a description.
Uses Googles chart API: http://code.google.com/apis/chart/types.html#qrcodes