More research

Some other relevant links:

App "ShopSavvy"
http://www.biggu.com/

Google Android scanning
http://ethicalspender.org/articles/pushVsPull
somewhat less interesting discussion
http://mobile.slashdot.org/article.pl?sid=08/09/28/2214203

Cuecat (similar device with a very different purpose, but an example of what can be done)
http://en.wikipedia.org/wiki/CueCat

CO2 Links:
Immediate dangers but also *some* uses
http://www.iprocessmart.com/techsmart/carbon_dioxide.htm

People that actually advocate CO2 emissions with potentially flawed theory (due mostly to oversimplification and ignorance/denial of facts)
http://www.bydesign.com/fossilfuels/greening_benefits/miracle.html

A surprising research on CO2 consumption in the food industry
http://www.biofuelsdigest.com/blog2/2008/09/26/carbon-dioxide-food-industry-applications-and-usage/

Food transport and CO2 emissions
http://www.climatechoices.org.uk/pages/food3.htm

How CO2 could affect marine biology
http://www.sciencedaily.com/releases/2007/12/071210103939.htm