There are a few good books out there for brushing up before interviews. "Ace the technical pilot interview" is a good one for brushing up on the technical aspects.
The most important thing, is be yourself, and know yourself. By that I mean, know what you have achieved in life, your experiences of leadership, teamwork, decision making etc, and have examples (prefferably more than 1) which can clearly illustrate these things.
As for what to take, that probably depends on the airline, however obviously take your license, logbooks etc.
Dress-code, I would have thought that was obvious. Unless your flying your 737 low level around the bush, I would avoid turning up in shorts, t-shirt and baseball cap.
Best of luck