I interviewed with T. Rowe, which is a buy side investment bank, about late last year in 09. They often came recruiting at my university so I became really interested because of its location in Baltimore City. I was contacted by HR after sending a few nice thank you letters after we met at our career fair for an official interview. The interview was a day long, starting at 8 AM, and I met with at least 9-10 people ranging from vice presidents to the investment fellows working at the bank. The people you interview work in different divisions in the bank and your essentially cycling through the divisions to were you fit. During lunch your invited by 2 investment fellows to a near by restaurant where they discuss your interests in the banks and your future career goals. There were some brain teaser questions, math quant related questions, and behavioral questions asked by the different interviewers in each division. They also asked me some current event questions about some of the products they offers.
Overall, T. Rowe Price is an OK investment bank, I was declined the offer and not knowing at the time, thank god I did, because I was offered a job at a better and more prestigious bank in NYC. No offense, but compared to the IB's in New York -- T.Rowe is a joke.
I would say the best way to prepare for this interview is make sure you the products that T.Rowe sells, up to date news and events and prepared for some of their quant questions. My interview with the bank was really early so make sure your brain is up and running at the time -- I would say that was my biggest problem during the interview because it was a long trip from where I lived.