Rand posted an update to a tool named keyword difficulty tool. The tool's name is pretty descriptive enough, it tells you how competitive a keyword is to rank for. There is great detail on how it works here and here.
I did a test on the term "seo blog" for no good reason. After waiting the specified amount of time, I was given a ton of details, which you can read in this pdf document (1.5MB) .
The Original Search Marketing Event is Back!
SES Denver (Oct 16) offers an intense day of learning all the critical aspects of search engine optimization (SEO) and paid search advertising (PPC). The mission of SES remains the same as it did from the start - to help you master being found on search engines. Register today!