I don't know which source you got that from. Here's one more reputable than some fanboy site. The NPD Group, heard of them?
For the year 2007, Xbox 360 sold 4.62 million units, PS3: 2.56 million. [1]
For the year 2008 through November, Xbox 360 sold 3,295,400 while PS3 sold 2,818,900. [2]
But, you know, you're almost right. Through most of 2008, PS3 was selling better than Xbox 360, but look at September, October, and especially November.
I shouldn't spend so much time responding to AC's, but I wanted to point out that this one is not informative, just providing misinformation and accusing all dissenters of being fanboys when it seems like this AC's bias may lean toward the PS3, or maybe they were simply uninformed.