I had 2 phone interviews with Amazon. I was invited to in-person interview after the first one that lasted about 2 hours. Couldn't go to Seattle at that time, so I declined. Recently, I had interviewed over the phone/online coding again. Haven't heard back yet, perhaps it's not been long enough. I feel their phone and online interview is a fair game for entry level position, consisting mostly of testing of general knowledge of data structures and algorithms. Trees, hash tables, list, algorithms used on them. I felt the interviews were testing knowledge of this subject matter mostly and questions were how to optimize/improve the algorithm also. Nothing too tricky or unusual. They didn't care which language one would use either.