Ask the individual admissions offices - I had one office tell me to bring a small photo, but only after I asked if there was anything I should bring. I've never needed anything at any other interviews though. I usually take a small portfolio folder with a notepad inside so that I can take notes on helpful information I get during the interview or financial aid meetings. I've often written down a lot. Plus it has given me a good place to store business cards or other papers they give me during the day (some of it has some personal information like grades, so you wouldn't necessarily just want to carry that around by itself all day). There's no need to take a resume or anything else though.
