Marco

This plugin will display a QR code in your sidebar which you can easily scan with your handphone or tablet and read later on the way home, to office or to school.

QR code generator

This plugin will display a QR code of the actually loaded page in your sidebar.

dweius

QutenizeR plugin for wordpress allows you to easily create personalized and colorful QR codes on the fly. <a href="http://qutenizer.com" title="qutenizer.com" rel="nofollow ugc">QutenizeR.com</a> is a free online Web service (beta) that generates full-color personalized QR codes on the fly. QutenizeR plugin for WordPress connects to it and get the images without leaving your blog’s admin pages. Feedback will be welcome. 
Enjoy this plugin!
This plugin uses Jan Odvárko’s JSColor available at http://jscolor.com

QutenizeR

QutenizeR plugin for WordPress is a funny way to easily create cute & colorful QR codes.

QR code generator vs QutenizeR