There are at least a dozen different "Free Credit Report," sites out there to choose from. The one that I've always recommended for a guaranteed, no hassle credit report is www.annualcreditreport.com.
This site is not only sponsored by the 3 major credit reporting agencies: TransUnion, Equifax, and Experian; but it's also the only one that really is completely free. Of course, there are some "extras," they may offer you (like the actual score) - but no harassment afterwards, and no worry about 3rd parties accessing to your personal info.
Remember, having a clean report (as in payment histories on revolving credit) dictates your score, and these can be checked for free through www.annualcreditreport.com.
Also, pulling your credit report is more than just your score - it's your first line of defense in keeping up with identity theft or fraud.
College students should be checking their credit reports at least once a year, maybe more if your especially "liberal" in your credit lines.
Working adults should be checking just as often. You can even check each report individually at different times of the year, to get throughout-the-year updates.
Happy New Year!