The process took 3 weeks. I interviewed at Google (New York, NY) in Aug 2010
Interview
Getting the Interview was relatively simple. I knew a couple of well-connected people there. Went in for an interview with 4 product managers (1 lunch casual interview) and 1 technical lead. All the Product Manager interviews went well. I stumbled on the Technical interview which was no surprise. I don't have a Computer Science background and have never productized anything on the web. My focus is on mobile products. So I knew that it was a long shot. And it wasn't a surprise when the recruiter called a week later and informed me that I wouldn't get an offer because of my lack of software experience and knowledge about the Web in general. For the record, I informed them that I had these blatant holes in their general requirements prior to the interview and they insisted that I go through the typical process. The folks I knew there that referred me wanted me to join Google because of specific experience I had from a previous employer.
Little grief over this - I'm not sure it would have been a good fit for me. I asked every interviewer whether Google was a Software company or a Product company. The unanimous response was Software. I'm a Product guy.
Very self-driven, first of multiple rounds, where I had to take the initiative to arrive at the problem, constraints, approach, solutions, tradeoffs and reasoning behind it in a matter of 30 minutes.
You would have to do a hiring assessment first, then a recruiter screening follows. First round interview with the hiring manager. Majorly product sense and product improvement. The questions were not direct though.
Overall a lot of steps to the interview process. Talked to different people and had opportunities to ask questions. Many different stages which made it a lengthy process overall. Wasn't too bad.