VS 2010 QR Codes

I'm starting to use QR Codes on a daily basis at work - right now, I'm going to this sketchy looking website to make them lol.
I know there are several programs out there that I could buy, but whats the fun in that?!

I'm interested in working on a QR Code Generator, as my next project.
Do any of you have any experience in this?
I really have no idea where to start on creating graphics from text strings.

Thanks for your help/input!