I had a fairly different experience since I didn't do any of the PwC internships or programs. I had one semester left before graduation and I actually went to a PwC Internship Presentation held at my university. I met with the HR director (who gave the presentation), told her about my interests, we chatted for a while and about two weeks later I got an invitation to do the "On Campus Interview".
The "On Campus Interview" was pretty relaxed my interviewer was extremely nice. She focused on getting to know me, allowed me to ask a lot of questions and gave me a few behavioral questions to answer. I didn't hear back for over a month and after that I calmly emailed my Interviewer about the status of my application. The next day I was contacted to schedule my "Office Visit" in my desired location. The office visit started around 9:00am (I didn't have a pre-interview dinner as I've seen in other posts). I was appointed a Tax Associate who showed me around the office, introduced me to some of his co-workers and took me to all three interviews. My office visit consisted of interviews with three Partners in the Tax area and each one lasted around 45 minutes. All three partners that interviewed me were extremely nice people and they all had a very nontraditional way of conducting their interviews, which I really enjoyed. After the interviews I had lunch with the Tax associate and his senior. Four hours later I was called and offered the job.
I am pretty sure that what got me into the interviews was my 6 month corporate tax experience (small firm), 3.92 GPA and knowing what area I wanted and exactly where. If you go to a PwC event and get the chance of talking to a recruiter you are going to be asked "In what area to you wish to intern or work and where?" Do not answer these questions with "I don't know." In the interviews per se focus on knowing your resume (work experience, activities , clubs, etc.) Besides that I would recommend practicing some normal behavioral questions, but don't over do it because then you'll sound like a robot reading through a script. Have lots and lots of questions for your interviewers, I again would recommend simple questions e.g. "How have you seen yourself change through the years since joining PwC?" (Partners really liked this question and I got really interesting answers). And finally, read about the company. PwC is a great place to work and for many reasons and they like to give back, this makes them very proud. You could, for example, read a little about PwC's contributions in Belize, Student loan repayments or their competitive benefits to their employees.
Best of luck to all.