Start with these sites for product innovation research:

http://web.archive.org/web/20080709054044/http://www.cbc.ca/kids/general/the-lab/history-of-invention/default.html

http://sciencenetlinks.com/esheets/history-of-inventions/

http://invention.smithsonian.org/resources/default_index.aspx#radio


http://www.enchantedlearning.com/inventors/

http://inventors.about.com/od/astartinventions/a/FamousInvention.htm

 http://www.explainthatstuff.com/timeline.html