Well, an '05 article from
USA Today (among many, many other sources) imply if-not-directly-state that the rights control for the Potter series is directly in Rowling's hands.
USA Today article link
And even more sources suggest that Rowling is quite anti-eBook oriented. And let's not forget that Bloomsbury holds many other titles (none, of course, with Potter's impact.) The TeleRead article suggests that if there's enough money in it, it'll happen. And maybe. I'm happily prepared to eat crow on this.
But I'm more than half tempted to say that Tony Glover is letting a sensational title, with little to nothing behind it, sell his article. Bloomsbury may indeed jump on the eBook bandwagon with the Kindle release - but that ain't even close to saying we'll see Harry Potter come to eBooks. *sad*