Marissa Mayer, Director of Consumer Web Products at Google recently made a post on the Google's corporate blog explaining Googlebombing. This was spurred by search results that point to President George Bush's White House biography when searching on the terms "failure" and "miserable failure" on Google. Ironically, Micheal Moore's website is the second search result for both of those search terms. Marissa says "determined pranksters" are responsible for influencing these terms search result and not Google. She explains how linking to the George Bush biography page while using the terms "miserable failure" as the text associated with that link repeated several times on different websites could cause search results to be affected.
A Consuming Experience wonders if Google is biased but brings up some good points on why they probably are not. While Connected Internet questions why Google has not yet fixed the problem since they have identified the cause and I agree that is a good question. However, I presume that if the problem was easy to fix without changing the backbone of Google's indexing algorithm they would have fixed the situation by now.