White Hat SEO: Keyword Density
Since keywords drive the search engines, it can be important that your primary keywords be optimized by frequency and placement. Keyword density alone is only one of a number of factors search engine spiders are examining to determine page ranking, but it can be helpful to look at the density of keywords your competition is using to find some good keywords or phrases you might not have thought of or noticed.
SEO Book’s Keyword Analyzer Tool
SEO Book offers a free Keyword Analyzer Tool that will give you a quick peek into your competitor’s sites to see what they’re doing and it can give you some insight into where you might improve performance on your own. It allows you to filter results by including or excluding Meta tag keywords and descriptions, and including stop words.