With second interviews coming up, two people have asked me what they should wear. I respond by asking what they wore the first time, and if they were comfortable in it. Then I say "wear the same thing."
Yes, wear the exact same outfit to your second interview that you wore to your first.
Two main reasons to do so:
1) You don't have to worry about whether the outfit is OK. Clearly it was, or you wouldn't be called back for the second interview. Really, inappropriately dressed interviewees don't get asked back, especially not in this employer's market for hiring. Wearing a comfortable and acceptable outfit relieves you of additional stress during an interview that could result in a job offer.
2) You will be familiar to those interviewing you. If they liked you in the first outfit, do a repeat performance. Once you get the job, there will be plenty of time to see what the "dress code" is at the office, and to wear different outfits. During an interview, it's wise to give them what they like. No one will notice that you're wearing the same thing, honest. You just are not that important to them - yet.
Keep it simple, sweetheart.
A note on interview outfits: it is always best to wear a suit. Dress up to indicate your respect for the employer, the occasion of an interview, the position and the opportunity. Look as good as you can! This applies to ALL interviews. Employers like to know that you take the interview seriously and that you respect them. It's always better to dress up than dress down. Dress down AFTER you get the job, and are sure that dressing casually is appropriate.