I applied out of college through their website. I was then flown out to Seattle for an onsite interview. The day started with everyone in a large group. They provided a pizza lunch and an opportunity to talk with amazon employees. I then had 4 back-to-back interivews each lasting 45 min to an hour. I stayed in the same room while each new interviewer came to me. The interviews consisted of a variety of general concept questions as well as programming problems where I wrote code on a white board.