A few days back we walked you through creating QR codes via the command line in Ubuntu.
Following that post a developer, David Green, put together a GUI front-end for the process, allowing for a more user-friendly experience in generating 2D barcodes.
The application, like the command line version, uses qrencode for barcode generating and allows you to specify text and pixel size.
A .deb installer for QR Code Creator can be found @ launchpad.net/qr-code-creator/
Alternatively it can be installed from the developers’ PPA @ ppa:david4dev/qr