Allan Roth describes his experience with CreditKarma.com and why it's so much better than all of the non-free credit score services in this CBS MoneyWatch article
When you sign up at CreditKarma, you automatically get free credit monitoring.
CreditKarma isn't alone in providing these solutions. I tried out CreditSesame.com and Quizzle.com. They also gave me a free credit score and report. While both very good, I found CreditKarma provided more information.
Some credit unions also provide free credit scores. Digital Credit Union is one that provides members with free Equifax FICO Credit Scores. I have more details in my free credit score