NOTE: Don't download this thing unless you just want to test how the 3D QR tag prints. If that is what you want to do I suggest the mirrored files. Otherwise to turn your QR tags into 3D QR tags just follow the instructions below and read the recommendation in the comments.
*******Back to the original programming************
I saw the latest post on the ThingiTag http://www.thingiverse.com/thing:8174 and wanted to figure out how to make the QR code printable.
Did a quick search and found the 2D Image to STL Converterhttp://www.thingiverse.com/thing:66115. and Voila!!!
So this is not an original but rather a set of instructions.
The QR code i tried this with is for my DryErase Bright Crayon Holderhttp://www.thingiverse.com/thing:72880
I haven't printed this yet to see how it comes out but when I do I will post the picture and test that when you scan it it takes you to the right page.
Update: I've now printed several 3D Thingi Tags and they print fine. One key step as mentioned in the comments is to enable the BW Threshold when turning the image to STL.
Mirroring the image before turning it into an STL will make a stamp for the Tag and ease the process of making many of the same tags.