10 keyword research tool

https://adwords.google.com/select/KeywordToolExternal
http://www.google.com/sktool/
http://www.google.com/trends
http://www.google.com/insights/search/
http://buzzlog.yahoo.com/overall/
http://clues.yahoo.com/
http://search.aol.com/aol/trends
http://www.bing.com/toolbox/keywords