Fox News has been on the "biased textbooks" trail lately - something that is hard to find definitive examples of but is generally believed by educators to be true.
I think some level of "bias" in textbooks should be expected: if the author of a textbook approaches the subject from a Christian worldview, I would expect that its tone and outlook to be different that a textbook written by avowed atheistic college professors. Duh. I've never found it to be a huge deal. It's far more important that a Christian teacher can spot anti-Christian bias and point it out to the students.
With that being said, some of the examples put forth in the following article are shocking - Jesus as a Palestinian is pretty bad. The promotion of Islam is true for most of the World History textbooks that I have seen.
Check out the clip of this special that ran a few days ago on Fox News: