I didn't know D* HD channel subscriber count was classified information. Sorry
As of May 8, 2008, DirecTV had 17 million HD subscribers. 7 million subscribe to both HD and DVR. That information was released in their Earnings Report.
Can not find the number of Dish HD subscribers. With three tiers of HD the number may be difficult to calculate. All that I could find is that their subscriber growth rate is very, very low. Wikipedia states that Dish hopes to have 14 million subscribers by the end of 2008. With low growth and loss of VOOM, that number is not likely to be achieved.