Business
According to a preliminary report released by Gartner Apple ranked fourth in U.S market share in Q4 2008 at 8.0% - up from 6.7% in the fourth quarter of 2007, but down from 9.5% in the third quarter of 2008.
MacRumors reports that the sequential decline in Apple's market share was not entirely unexpected because Apple traditionally does well in the back-to-school third quarter which typically results in a weaker fourth quarter of each calendar year.
You can read the complete report at Gartner.com.