Help me prepare! (updated)

So ladies, I have an interview for a promotion next week. Background: I have been at my job almost 7 years and have already interviewed for this position twice. They have moved 5 other employees into this position since I first applied. The last time I interviewed I was given less than 24 hours notice of the interview and it was exactly a week before I have birth (everyone else had several days to a week notice). I really had no intention to apply for the position again, but then my direct supervisor took another position in ie organization, so now they are looking for someone to lead my current team. I know my co-workers, direct supervisor, and her supervisor (who was previously my direct sup) want me to get the job, and I don't want to let them (or myself) down.

So- how do you prepare for an interview? Especially an internal one? What questions have you been asked? Any other advice or words of wisdom?

Update: I left my interview today thinking it went very well! I definitely think it was my best interview and this is really the best timing there has been for me. I am trying not to get my hopes up too much though. Hopefully I will know the decision by the end of the week. Thanks for your thoughts/suggestions ladies!