My interview was last August.
Day 1; (business casual) Evening meet and greet . Question and answer, overview on the company power point presentation and beer (seriously)
Day 2; (business casual) @ Air Inc. The sim ride was in a very pitch sensitive desktop simulator with a very primitive visual; Flap and gear operator will set all the configurations for you and handle the thrust levers until you're ready to level off....no call-outs required. Depart LAX, vectors, join a couple of radials and intercept some NDB bearings, holding entries (just say how you'll enter, not actually make the entry) and vectors to an ILS. Don't get low and slow as it is almost impossible to recover when fully configured. They don't judge you on the landing but they want to see you do it.....I put tire tracks in the grass beside the runway and they still hired me.
They provided pizza for lunch.
The other half of the day is dedicated to computer testing. Half the group did the sim first, computer test second. Vice versa for the other half. The test included math, psychological questions and word problems. Just be honest and don't try to trick the psych part. Then everyone goes for a drug screen.
Day 3 (suit and tie); Panel interview. Mine was with the assistant CP, a line Captain, and an HR woman and it lasted about 25 minutes. I was asked to describe my aviation career and why I think I would fit in at World. There was one TMAAT question and they wanted me to tell them why someone would be able to get along with me on a 10 hour leg. Overall, it was pretty relaxed.
I stayed at the Wellesley Inn ($50 at the time if you asked for the World rate) and the panel interview was conducted there in a conference room. It made it so much easier to hang out in the hotel in my boxers until the interview time (determined by when your flight home departed ATL). Then I just walked down the hall from my room to the conference room. I wore my suit for no more than an hour.
I hear that sometimes the sim rides are in a 737 simulator at the Delta training center. Also, I heard that the formal interview is sometimes on day 2 and the sim/computer testing is on day 3.
Good luck!