RankScanner is a free service that automatically monitors your keywords' positions and rankings on Google.
With RankScanner, you can track your keywords and SEO efforts automatically on Google, without having to check the SERPs (Search Engine Ranking Positions) manually.
Simply add keywords to monitor on app.rankscanner.com - after adding your blog’s domain address - and the tracking begins automatically. Reports are generated real time, and keywords will be checked at least once a month.
Visually analyze your SEO performance with interactive graphs and statistics
You will need a valid RankScanner account (which is free) to use the RankScanner WordPress plugin. RankScanner is currently in a closed BETA, but everyone can sign up and gain access quickly.