Tommi at S60 Applications Blog has a great 10-point manifesto about 2D barcodes called The 2D Barcode Manifesto
Now, we are finally about to put Nokia's Barcode Reader application under N80 and N73 support pages, and to the Download! client. In addition, the app should be in the latest N93 firmware in all variants.
I wanted to publish this post on the day that the app becomes available, but I'll be on vacation during 13-26 December. I hope the app becomes available during this time.
Lots of great reading and links in this, even a couple contributions from The Pondering Primate.