hmm i always figured since they flew the seminoles with two students in them, that they used the hood so both could log it. i guess matt will just have to chime in here and set me straight.
In the words of Ed McMahon "You are correct, sir!" In the ATP program, once you finish your instrument rating, you go through 5 hours in the sim and 3 hours in the plane of CRM and dual pilot training. In the sim it's all about diagnosing and handling failures as a two pilot crew (everything from slow engine over temp to total com failures, and pretty much everything else the sim can do). In the plane it's more like a LOFT flight...with an instructor you fly one way (I went from PHX to YUM) in the left seat as the FP only - he handles the radios and navigation. Then on the way back, you do everything from the right seat to get used to things over there.
Once you're done and signed off from that, you're released to ATP "Dispatch" and turned lose on your cross countries. Every morning by 0730 you call in, they give you a partner, a tail number, and a destination. From there it's up to you and your partner to get the plane ready, do the preflight, get filed, and get in the air by 0930ish. Everything is flown as a two pilot crew, with the PF "under the hood" and the PNF handling the radios, GPSs, charts, etc. It's up to you and your partner to decide who sits in which seat, but this whole thing is designed to foster good CRM, verbal checklist usage, and use of callouts (ATP's callouts are very similar to what we use here at CJC, so they seem to be basing them on what some airlines use).
The 75 hours isn't all as the PF, though. As Tony said, it's half PF and half NFP. The PF is always
supposed to be under the hood, and logs time from the Out/In hobbs (engine hobbs) and the PNF logs time from the Off/On hobbs (tied to the squat switch on new planes and an aerodynamic switch next to the pitot tube on the older planes). I don't think they'd be nearly as profitable as they are if they had to give 75 hours to everyone that comes through there, and I think they got some kind of insurance break for being able to always say that there's two pilots in the planes.
Once you're done with the cross countries you have, I think, 3-5 hours with an instructor again before going up for your commercial multi ride.