I got a phone call from Amazon recruiter. Initially deleted the voice message, because I knew that it is pretty hard to get into Amazon, and I didn't feel like I will be able to do it. Later changed my mind and responded back with email a week later and we scheduled a first phone screen.
The 1st PS was ok. After reading some of the suggestions on this site I was able to prepare for it.
Wherestions were about DOCTYPEs, positioning and display CSS propertties, page latency, web dev best practices, OO JS, was asked to code a specific page widget and send the code to the interviewer. Got response from the recruiter back within 2-3 days requesting appropriate time slot for a second PS.
The 2nd PS was a little harder, but within the same difficulty range and similar sets of questions. More of a CSS and JS questions. DOCTYPEs, latency, OO JS best practices.... In about 3-4 days got response from the recruiter saying that Amazon wants to move on to in-person interview.
In-person interview is a little different than phone screens. The PS is a set of questions all over the board.
During In-person interview there are 4-5 guys and each of them has a specific goal, a specific set of skills to test. all of it is related to your potential future job, but one might check your technical skills, another is your problem solving skills, another is "deep dive" into specific areas needed for the position they are trying to fill. etc. It is important to identify early which areas each of them is looking for so that you can "strike the right notes". Also it is important to know who the bar raiser is. He will set the tone of the interview, he will have the last word on the decision.
Every single person I talked with or met (during PSs or in-person) were very nice, pretty smart, good at what they do and .... nice. They are not trying to make your life harder. They are trying to find the right person for the job. Some of them might be the guys you going to be working with, or there might be none from the hiring team. But believe it or not, they all try to make it easier for you to do your best during the interview.
Also, your skill set is not the only thing they are looking at. It is also how you fit into the teams culture, your personality, how you relate to what you do. So be yourself.