It will be Grammy-nominated songwriter Kara DioGuardi.
She's said to be smart, sassy, and will make the judges panel consist of 2 guys and 2 gals--making it even.
What's really going on? 2 things, I suspect: 1] "Idol" producers would be delighted to find a female Simon Cowell. 2] They don't want "Idol" to become stale; hence, they add something new. In American television and showbiz generally, it's "be willing to change--or die."