Professor Sybill Trelawney is Harry Potter's Divination Teacher in his third and fourth year at Hogwarts School of Witchcraft and Wizardry. She is considered to be a pest in Harry's eyes, a woman with huge glasses that make her eyes look buggy. She has blonde hair and a very flowing attitude and also wears a lot of jewllery. Her fortunes don't always turn up right or wrong, and she spies Harry's future as being dangerous and dark-- which Hermione refuses to believe. It also seems Professor McGonagall considers Sybill to be a bit of a exaggerater and paranoid person as well. It seems to Harry that no one take Sybill seriously anymore. She constantly predicts Harry's death, and is the antithesis of Professor McGonagall and Hermione. She predicts the return on Wormtail to his master, and that the Dark Lord will rise again, greater and more terrible than before. Which Dumbledore comments must be her second real prediction. Makes you wonder what her first one was.
Sybill has yet to be cast, but one of the nominees is Emma Chambers (Notting Hill) whose picture is used in the layout. I personally hope she gets it.
Part of the character description was taken from Filling the Shoes.