I applied online from a non-target school. KPMG doesn't recruit from many schools without finance or accounting programs, but if you have an interest in working in their consulting arm you should get in touch with an advisory recruiter. I had a brief phone screen before the start of fall recruitment. I was contacted for an in-office final round interview because the firm does not do round one's on my campus.
The final round consisted of two formal interviews with a manager and a director and one informal interview with a senior associate. After that I was taken to lunch with several associates, a couple of managers, and the other candidates. My understanding is that previously the firm's policy was to primarily focus on behavioral interviews in the final round but that has since changed. There were four cases, two fairly standard human capital cases, one ethical case and one excel case. The excel case was somewhat unique in that I was not asked to actually perform a task in excel, but rather to explain verbally how I would go about a task that was described to me. The interviewers were very helpful and clearly want you to succeed. Everyone was extremely friendly and loved talking about the firm. The luncheon was a great chance to hear more about everyday life and the community in P&C at KPMG. I received a call with an offer about a week later.
I would recommend familiarizing yourself with human capital concepts and excel, and networking within the department if you can. It isn't terribly large and everyone kind of knows everyone so being able to name-drop actually does go a long way. Behavioral questions are straightforward, be yourself and you'll do fine on those. The people are very down-to-earth and mostly want to see that you'll fit in and understand the type of work they do.