As your credit report can affect your borrowing power, and, at least in the US, what interest rate you are charged, it is important to obtain and check what information the credit agencies have on you.
The NYT had a good article on this topic today, relevant to US readers. Main points are:
* There is only one Web site—www.annualcreditreport.com—where you can either download or order your free reports by phone or mail (the toll-free number is (877) 322-8228).
* You should check your report once a year and correct any errors.
For Australian readers, two main agencies maintain credit databases, and you need to obtain and check the report from each. This will cost a fee(eg. $27 from Baycorp) if you apply online. If you write in and ask for a copy of your details you can get it for free in around 10 days. (They obviously want to make it as hard as possible to make a "free" request.). A form is available online from Baycorp Advantage and Dun and Bradstreet.
There is good information on what's included in your credit reports available from here. The most relevant bit is
"If requested in writing, credit reporting agencies must provide you a report detailing all records on your file. The credit provider must provide a copy of your file within 10 working days of receiving your written request. Section 33 of the South Australian Fair Trading Act 1987 states that this must be provided free of charge to South Australians. If you require a copy urgently, you can request this online or by fax. However, a fee will be charged for this express service."
Most other states have similar legislation, so just write in and ask for a copy of your report from each agency.