Well, looks like my X3 gossip was wrong. The person I was told would be dirtect the movie is not. Instead, they have announced Rush Hour director Brett Ratner will take over the film. From Newsarama:
With last week's announced departure of X3 director Matthew Vaughn, a mutant-tinged vacuum was created. Today, Variety confirmed that the director's seat for the third X-Men film installment will be filled by Brett Ratner. According to the trade, the director of Rush Hour among other films, is eyeing an August production start, with no change in the film's planned Memorial Day 2006 opening. Variety also stated that Ratner was on the short list of directors for the first X-Men film, which went to Bryan Singer.
The report also confirms that Lost star Maggie Grace will play Kitty Pryde in the film.