In addition to the great market news and vendor list provided by the pondering primate, Jump! Mobile in his blog has a post with all the blogs that discuss mobile code scanning. there are vendors, marketers, mobile social networkers and much more. Excellent stuff from Jump! Mobile.
Let me quickly repeat the list of mobile code blogs for convenience (from Jump! Mobile):
Rex's blah blah blah (Chinese) - One of the most informative introductions to 2D barcodes and with great industry insight.
The Pondering Primate - Probably the blog that coined the term "physical world connection", always up to date on the latest developments on mobile barcodes.
QR Code Blog (Japanese) - Though discontinued, the blog's attempt at blogging with QR Codes is still quite interesting to see.
All About Mobile Life - Kaywa expert's blog always has something nice to share.
Bar code Insight (Chinese) - Observes the mobile barcode developments happening in Mainland China.
Tommi's S60 applications blog - Developer at Nokia shares views on mobile barcode applications.
GSMBLOG.net - Has an in depth review and comparison of various 2D barcode readers.
David Harper's Different Things - WinkSite founder introduces QR Codes.
BeeTagg Mobile Tagging Blog (Swiss) - BeeTagg's official blog.
streetstylz - NeoMedia's official blog, I think.
Make a Difference - Blog by NextCode's director of product management .
ShotCode Blog - ShotCode's official blog.
http://semacode.org/weblog/ - Semacode blog
http://www.semapedia.org/wordpress/ - Semapedia blog
http://barcode20.blogspot.com/ - Olivier Attia blog - Founder of Scanbuy
http://blog.announcemobile.com/ - Jeff Mould blog - Founder of Announce Mobile