I applied to a Product Manager position at Google online. About 2/3 weeks later, the HR contacted me via email I was selected as a candidate. The HR sent a list of information for me to prepare for the interview, including the job description, tips on things to know, and type of interview questions expected. I was also asked to answer some questions briefly such as what's my favorite google product, preferred location etc. It was right before the Christmas holiday so the interview was scheduled about a week after the new year. I had the luxury of the entire two weeks to prepare for it.
It was a 45 minute phone interview with one of the product manager. I found it a bit hard to interact with somebody over the phone especially when answering about product design questions, because I cannot observe the reaction of the other end.
It was a good experience overall. The last question was about algorithm and run time. It was actually quite simple when I thought about it afterward, but at the time, I wasn't being very smart about it. I had a computer engineering degree, but have not done programming in years. Also, this was the first interview I had in couple of years. So I felt a bit rusty, especially answering the technical question.
To prepare, I read a lot of technical interview examples and followed the Google product news and user feedback for a while to get familiar.