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) .
Meet Your Favorite Search Engine Watch Contributors
Many of SEW's leading expert contributors will be at ClickZ Live, the new online and digital marketing event kicking off in New York (March 31-April 3). Hear from the likes of: Thom Craver, Josh Braaten, Lisa Barone, Simon Heseltine, Josh McCoy, Lisa Raehsler, Greg Jarboe, Dan Cristo, Joseph Kerschbaum, John Gagnon, Eric Enge and more!