Interview process was approximately 3.5 months long.
Got a phone call about 3 months after I applied asking if I wanted to interview. if you live in on the mainland they will have you fly in to either LA or Denver for an interview. You're on your own for getting to the interview. You have to either buy your own airline ticket or gas if driving and pay for a hotel/rental car if necessary.
The interview itself was about 2 hours. It was like taking an instrument/commercial check ride. The first part was the oral which included HR type questions and technical questions. The second part was a sim evaluation in a red bird motion simulator and you will shoot approaches, holds, do steep turns, etc all in IMC of course.
If they like what they see they'll offer you at the end of the interview and give you available dates for upcoming classes. Training is in Hawaii and you have to once again pay your own way to get there. You also don't get paid until after you pass training/checkride (approximately 3 weeks long).