Good luck in the interview.
http://www.monster.co.uk
has loads of info on interviews etc. My routine is this, go to the location of the interview if possible before the interview so that 1. you know exactly where it is 2. find out any potential trouble spots, maps never show all the little cars in long chains. I always plan to be at the place and hour (yes an hour) before hand, I don't go in early (makes you look like this is the only thing you have to do all day) about 10 minutes before is a good time. Always wear a suit, and I mean always even if they say smart casual is fine and try to make sure you suit has been cleaned before you go. Try and think what they will ask you and try to think in as much detail as possible what you would say in reply. If they ask you to tell them about yourself (most jobs do but might not in your case) don't take this as an invitation to talk about your Frog collection its a great opportunity to talk about you career and work achievements. Also try and think of a number of reason why you want the job because they will ask you. Also one important thing is to try and think up at least 6 questions to ask them as they will always ask if you have any, they will more than likely have answered 2-3 in the course of the interview, so that leaves 3 in reserve. Try and relax and good luck.