I had just been reading that. Aljazeera seems quite unbiased in its news reporting. (not what I wrongly assumed it was like before I started looking at their news coverage a while ago now )
Al Jazeera, as you would expect, is biased when it comes to matter concerning Islam and the Middle East. They are, after all, owned by the government of Qatar. Despite being set up as a "Foundation for Public Benefit" and having a considerable amount of genuine editorial independence they are unashamedly Islamist and pro-Qatar, pro-Sunni and anti-Shia.
However, aside from that one blatantly obvious area of bias in matters concerning Islam and the Middle East, they are OTHERWISE surprisingly unbiased and very informative on pretty much everything else.