Anything that a "credit repair company" can do, you can do yourself. It may not happen overnight, but with a little work, some reading, you can do exactly what they do - and without their cost.
Thats one of the reasons why sites like this exist. To help you out.
What specifically are you looking to do?
have you pulled your credit reports and reviewed for factual and correct information? That's usually the first step to starting your credit repair.
We're all here to help, what's your goal?