I received an email late in February inviting me to participate in two phone interviews to gauge fit and aptitude for the position. I completed the two interviews and received my offer by phone two weeks later. Note: I was studying abroad at the time.
The recruiters usually got back to me pretty quickly and answered my questions well. The interviews themselves were very casual. One interviewer seemed more interested in the social/fit aspect, the other asked more situational questions. My position is pretty far-removed from the product development and engineering side of Google, so nothing was asked about the company, the business model, etc.