Khoi Vinh has some solid tips for interviewees about how they should prep for an interview with his firm, Behavior. Vinh's suggestions essentially speak to interviewees giving their interviewers good service: look the part, do your homework, be prepared for the worst, and complete the exchange graciously.
Incidentally, Vinh's award-winning blog, Subtraction, is a gorgeous study in grid-based design, as well-handled as any website I've seen. (Vinh details his process in another entry on his blog.) Monochrome, with strong, understated typrography, and he's designing with Fitts's Law in mind (the nav bar at top has plenty of nice, fat click targets, as mentioned in my first post). Exceptional.