1 phone interview, 1 on-site before granted an offer, the whole process took ~4 months. (delayed due to gov shutdown) I sent in my resume in early June 2013, briefly talked through phone in July and was invited for an onsite interview in Aug. The interview was pretty standard for the postdoc postion. 50min talk in PhD research in the morning, followed by few 1-on-1 talk with future boss and colleague in the morning and afternoon. Most questions are research specific, no behavior questions. I was given the offer by phone one week later, but the offical letter from HR took another month.