Dell's fortunes have been closely tied to some of its suppliers for a long time in the computer industry. When Microsoft makes a turd OS like Vista, sales of PCs for Dell aren't that great. When Intel offers Dell special deals on chips to not use AMD, Dell gets into trouble for not telling investors those incentives affect the bottom line. You get the deal.
I take statements by Michael Dell with a big grain of salt when talking about anything from Microsoft. Dell has stated at an event in Hong Kong that it is easier to develop for Windows Phone 7 than it is for Android.
He also stated at the same show that Dell would be tossing a number of new tablets onto the market in 2011. Dell has already tipped that a new 7-inch Android tablet was coming and is expected at any time now.