PepsiCo was very hands-on in terms of following up and letting me know the upcoming steps in the interview process. They were very friendly both on the phone and in person. When I went to interview at their HQ in Purchase, NY, I first met with a recruiter. She was very friendly and asked questions regarding my background and what I was studying, less technical questions. The next day I went in and interviewed with four senior-level people in the Internal Reporting department. The first was my acquaintance at the firm, so she and I discussed the internship and I wasn't grilled on anything. The next three however were very curious as to why I wanted a summer internship with PepsiCo when I wasn't an accounting major, and I reassured them that I wanted the position because any job is a learning experience and both PepsiCo and I would inevitably gain from it. All in all, not too stressful, but they care about quality people, so make sure to do your homework before coming in for an interview.
Also, forgot to mention the drug test and background check they do on all potential employees.