I have some experience in cleaning up my credit report. My reports showed addresses that didn't belong to me, a collection that wasn't mine, and my birth year as being 1924 (yeah, right...I'm 79 years old and a sophomore in college). You'll need to obtain a copy of your credit report from each of the three major credit agencies (Equifax, Experian, and TransUnion). You can get all of them online (do a web search...I don't have the links handy) and you have a few different options for doing so. The easiest thing to do would be to get a 3 bureau credit report which does a line by line comparison of all 3 agencies. You can also get your scores from each of the three. Anyway, when you get the reports, you have the option of disputing items on them. Equifax and Experian both provide a means to dispute them online. TransUnion, however, requires that you send them a letter detailing the inaccuracies and reasons why they are inaccurate. Definitely dispute anything not belonging to you. You can also dispute things that actually do belong to you in hopes of getting them taken off your credit report (I'm told that this works about half the time). Using these methods I was able to increase my Equifax credit score by about 130 points over 6 months.
Hope this helps....