"Father Amorth, who is president of the International Association of Exorcists, said of the JK Rowling books:"Behind Harry Potter hides the signature of the king of the darkness, the devil."
At this point, the magic is a kind of fantasy-access to powers of good or evil, like the magic practiced by Arwen and Galadriel in Lord of the Rings. And Harry (like all of Rowling's positively-presented characters) is portrayed as struggling against evil, and using his strengths to protect the innocent. The good powers don't involve accessing rebellious spirits, but merely using a kind of alternative technology.
Now in the 7th volume, if he really does go over to the Dark Side, I may have to change my evaluation. But I don't think that's going to happen.