Don't fall for anyone advertising that they can help you clean up your credit report. The only way to do it, other than correcting errors in it which you can do by writing the credit company and disputing the information, is keep your credit clean. After approximately 5 years, you should have a good enough score to get a credit card with reasonable interest rates. However, my experience has been it is not necessary to have credit cards for any reason, pay cash, use PayPal (which is a debit card that withdraws from your bank account without disclosing your information to the merchant), get a debit card to order on-line, and when you get your money it is still yours. Sorry, there are no quick fixes and companies that tell you there is are just not telling the truth.
I found a link that has some great information on what to do and not do (they agree with Koichan about beware of people claiming to "fix it" for you). These are good tips to follow even if your credit is still good, but they also have suggestions on how to improve your score, too. It will take time, but it certainly can be done. NOTE: This also seems to be a site selling help with credit, just FYI, but I know nothing about them so I can't vouch yea or nay. But the info on this page (link) is real and very helpful, at least, and is all stuff you can do for yourself: http://www.myfico.com/crediteducation/improveyourscore.aspx Hope this helps! :)