I am very interested in the use of QR Codes.
Last week I received a link to Twi-QR which offers the facility to generate:
Your unique QR code into which your profile image on Twitter is embedded comes up in a few seconds. You can store the design QR code and then show or email your friend to scan the code. Please feel free to put the design QR code on your blog, Facebook, and etc.
Here is my Twi-QR design.