Well, first off this isn't going to be a super detailed gouge. The other gouges on here and aviationinterviews.com have the gouge right on.
I put in my app on the 4/18, it went to screening on 4/30. On 5/3 they sent me an email asking what dates I was able to interview, they gave me the choices of May 7/8 or 14/15 (I chose the 14/15). I emailed back that morning, and by 1500 they emailed me with my flight info, and the information I was going to need to bring with me. So it can happen pretty quick.
My best advice is to get all the required paper work in order before you ever apply. Make sure you logbook/resume is up to date, SS Card, FCC lisc., passport, school diplomas/transcripts etc, are all ready. It will save you from having to run around at the last minute, so you can focus more on studying. Make a Word doc with all your 10 year employment/address history so it's all in one spot. The more organized you are for the interview the easier it will be to fill out all the paper work.
Study the gouges on aviationinterviews and you will be fine. Also, what ever twin you have the most time in, know it well. Be able to explain all the systems and speeds. I was flying the Lear 45 so they really hit me with a lot of questions about it. The more complex the A/C is, I think they tend to ask more questions about it.
They are really great people to interview with, and will make you feel at ease, so just relax. I know it's been said, but they want to hire you, don't give them a reason not to.
Feel free to PM with any other questions.
Almost forgot, I had 775/295. I start class on 6/04.
Mark