SEO-WATCH provides free tools for SEO and website research.
Keyword Density Checker
The Keyword Density Checker tool extracts keywords from a website and determines how often they occur. Get a list of one-word, two-word, and three-word keyphrases organized by keyword density. Check the keyword density of a site to see how search engines view your content, optimize your keyword density, and research keyword trends on any site.
Extract keywords from any website and create a list of single, double, and triple word keyphrases.