From: http://qrcode.sourceforge.jp/:

“QR Code is a two-dimensional barcode, used widely in Japan. The advantage of QR Code from well-known barcode is larger data capacity (more than 100 bytes, typically) and error correction.”

Thanks to an idea from Tom Igoe, I make a quick and dirty interface for Processing for QRCode decoding. The Pqrcode library page is here.

Also, qrcode images can be generated here.