This was a rare case where Google was interviewing into a specific group (usually they just hire smart people and assign you later). This was for Admob, a google acquisition, which is a rich-ad network for mobile. First step was HR rep, who was also ex Admob. Very nice, very straightforward. Brief chat, and basically wanted to know why i wanted to leave where i was at. Second phone interview was with a product mgr at admob. Very nice person, easy to talk to. Seemed genuinely interested in me even though I'm sure he had been interviewing a lot of people. At first, it was mostly me just talking about the experience on my resume. He would ask questions as we went along - how did you design this, and how did you measure how well your app performed.