Is there any package that generates 2d barcodes (QR code). I want to add a barcode on the front page of a manual I have written containing the URL where to download that manual. It would be nice if I could continue using pdflatex. Instead of converting each time.
EDIT: [Reaction to Jake's answer]
Is it possible one could only add one barcode. I've analyzed how this works. I think the compiler runs two times, one time rendering the pstricks images. A second time inserting the images in the LaTeX pdf. However if I add two different barcodes. It simply overides the file by the last barcode, and uses this file for both the barcodes. Is there any workaround for this problem?

auto-pst-pdf, you don't need to go through the conversion step. See my answer. – Jake Feb 08 '11 at 11:52auto-pst-pdfpackage – Feb 08 '11 at 12:39