Another suggestion Matt makes is to claim your name to stop someone impersonating you. The way to do this is to register your name as a username on all the most popular sites such as Facebook, Twitter and YouTube. He also recommends registering your name as a .com domain, which can be done via GoDaddy.com for $10 per year.
If, when you search for your name, you come across content that you or others have posted that you would rather not be there, you can request that the information is removed. This can work out costly in both time and money, and as I found out a few years ago when I tried to help a friend who had a malicious Facebook group set up by students about her, it's very difficult to get content that someone else has posted about you removed in this way, just because you don't like it. In this situation it's possibly a better option to "bury" what you don't want showing up on the first page of the search results by adding as much positive content about yourself as possible and then making sure this content shows up high in the search results. This can often be achieved by cross-linking your content between the different tools.
Image by Fadhila Brahimi, 2000