I was toying around with Google Insights tonight and figured it was worth a bookmark! It shows trending on a search phrase over time, states searching for the respective phrase... and other things... like popular keywords related to phrase!
http://www.google.com/insights/search/
And you can always use this guy, the Google Adwords Keyword tool...
https://adwords.google.com/o/Targeting/Explorer?__c=1000000000&__u=1000000000&ideaRequestType=KEYWORD_IDEAS
