Does anyone know of any good online tools that allow you to find out where your site is ranked in Google?

Having recently been giving the working role of SEO person on a number of websites ran by my company I was wondering if anyone knows of any good online applications that let you see how your site ranks in Google based on they keywords you are using? Especially for those sites that aren’t yet making it into the top 10 pages of google – it can be quite a trawl to check where you are.