I just published a new bit of open source code, a small service in Sinatra for generating branded QR codes with a logo. For example, this page can be found with this QR-code:
It's simple to use, and to configure, at least for a Ruby programmer - just set up the base URL and the logo, and then call the service with whatever you want appended to the base URL. It returns a PNG image, cached with Redis for speed. Clear instructions are available on the repository.