google has its own keword density analyzer... Look here. https://adwords.google.com/select/KeywordToolExternal
Go after the keywords that are searched more often. Why optimize for keywords that are never searched?
Ok, I appreciate that answer - but I mean a good tool that shows you which keywords are searched by frequency. I know you need to go down the list and evaluate the competition for said keyword, so the most obvious choice gramatically may not be the best choice to compete for. Thanks, Ronnie Springer
you can check it through couple of rank checking tools. like google for free monitor and rank checker.
This tool can check your rank for a given keyword up to 1000th position: http://www.seoserp.com/google_page_rank/1000_serp.asp
I like using the google webmaster tools, as they show the top keywords they found when crawling your site, and lists times where your website has been included in search results and where you ranked in those results.