There are quite a few QR Code generators online. Some of them like Barcode Maker simply cosmeticize the Google Chart API while others like ZXing have full MECARD encoding. Here are the best examples:
QR Code and 2D Code Generator
Kerem Erkan has produced an excellent QR Code, Micro QR Code, Datamatrix and Aztec Code
generator with many interesting features including URL shortening.
Configure size, version, error correction etc., and save as PNG, TIFF, JPEG, GIF, XAML, SVG, EPS or all in a ZIP file.
Online Barcode Generator
Generates QR Codes and almost all other known barcode types, error correction and EPS download available.
Jason Delport’s Create QR Code
User interface for the Google Chart API with 500px x 500px maximum size.
50px x 50px images can be inserted in the code and output can be saved as gif or pdf.
QR Codes and Datamatrix codes at small, medium and large sizes.
One size but generates a QR Code and a Datamarix Code simultaneously.
Select encoding mode, multiple colors and upload background graphic.
Any color background or modules and many other options.
QReate & Track
Includes iCalendar and vCard formats and an option for real-time reporting.
Lots of options here including color, batch printing with Avery label compatibility and send by email.
Can specify error correction levels.
Informatix QR-Code Generator
Allows different colours and shapes to be applied to the QR Code data blocks including the overlay of readable text and images. Displays the validity of the QR Code indicating if it is likely to be successfully scanned or not.
Visual QR Code generator, turn any image into a QR Code.
PNG and JPG in standard sizes.
Stand alone Decoder and Encoder