A recruiter got in contact with me. He was extremely friendly and excited to help me. He sent me interviewing tips and a cheat sheet of what to expect. I had 3 phone interviews and 4 one-on-one interviews (on-site). All of the interviews were extremely well-prepared. All interviews stayed exactly or less than 45 minutes. They seem to be very strict as to the duration of each interview. So if there was a tip I would give, it is to not talk too much and let the interviewer ask his questions so you have more time to solve the technical problems. In the end, this is what will matter.
I would study up on at least the following: BFS, DFS, Hashtables, String Manipulation, Trees.
For my level (3 years out of college) I did not find the algorithm questions to be anything that would be too hard. They are all answerable within 45 minutes. The key is to be able to understand the problem and identify an efficient solution as fast as possible. Also, the implementation is very key. Knowing to use BFS is not enough, you need to be able to implement it very fast too.
I cannot provide you guys with the exact questions because I respect Google's NDA. However, the following are the kinds of questions that I was asked. I think as long as you are able to comfortably and accurately answer those types of questions in 45 minutes you will be fine (I usually get asked 2 algorithm questions in a 45 minute session).