I recently went through a "behaviorial interview." I guess it didn't go so well, I didn't get the job. This type of interview asks about possible situations and how you would handle them. My advice is be prepared for this type of interview. Research interview questions on the internet and practice what you are going to say.
Also dress to the nines......it's okay to be dressed a little nicer than your interviewer. Look professional, not cheap.
If you have a already have a job and have an interview scheduled on your work day, then I reccommend taking a day off. This is where I failed the interview......I dressed a little more on the casual side because I didn't want my current employer to suspect anything. My mind was not clear and focused for the interview mode......therefore my answers were vague.