I found a webpage that gives informtion on Ravenclaw. Did you know that the The Grey Lady is the house ghost?

Yep, "This information was verified by JK Rowling. She has said readers have already "met" The Grey Lady in book 1 (she passed by Harry) and will be introduced to her in future books."

And that the Head of the House is Professor Flitwick? Well, now you do!

Find out more here.