I have been told it's a good way of keeping a check for Identity Fraud.
if you are looking for the free credit check usa national site, check out this site
http://free-credit-check-national.com/
Here you can check your 3-in-1 Report from all three credit reporting agencies and your credit score rating.
look here
http://answers.yahoo.com/question/index;_ylt=ApbpgMLKJh7Aj0Rqxvsou5YjzKIX;_ylv=3?qid=20091017112505AAR8OpH
other wise there are services like freecreditreport.com - where you get a trail membership and after that they charge you a fee - but you can watch your credit score