I recruited from my university, so they had the whole process already set up. I originally interviewed for an internship which then led to a full time position. I attended a few meet and greets with a bunch of firms and them applied for interviews. We did first round interviews with partners at my school. Since I was interviewing for a job in NYC and my school is in TX, I could only get a general idea of the firm culture and not really anything specific about the office or the people I'd be working with. The interviews are extremely informal (generally the norm for all the Big 4 firms). The partner I interviewed with asked me a couple of basic behavioral questions (e.g. Top 3 strengths/weaknesses, negative team experience, etc.). Also, if you plan on recruiting for an office in another part of the country/world, be ready to let them know you are SERIOUS about working long term in that location. This was probably the biggest issue most candidates had from my school that were trying to get to NY. Having family or previous experience in the area you're trying to go helps.
After making it through first rounds, we got invited to office visits. This consisted of three interviews. One was with an HR manager, another with a manager, and the last one was with a partner. These were all very conversational and only lasted 30-45 minutes. At this point, they're basically just making sure you aren't awkward or weird or anything. Just don't screw it up and you're all set. After the interviews, we went to lunch and the day was done by 2! I heard back that same day that I had an offer for the internship. It was a really long recruiting process (Jan - May), but overall it was fun and relatively stress-free.
My biggest piece of advice is to make sure that you REALLY want to work in public accounting or that this job will get you somewhere you want to be. I see so many people (including myself) that get caught in the trap of "it's what everyone else is doing, so I should probably do it too" that they forget to ask themselves if this is REALLY want they want to be doing. Just my two cents.. Anyways everyone, just show these firms your awesome personalities and let them know that you really want to work for them and I'm sure you'll have no trouble getting a job!! :) Good luck everyone!