I was contacted by a Google recruiter and was asked to rank myself on various topics such as programming languages, Linux, and Networking. I was then asked some relatively simple questions on the areas I ranked myself highest.
This was followed by 3 additional phone interviews, 2 on technical topics including programming problems using Google Docs, and 1 on project management.
The whole phone process took about 2 months. After that I was flown out to Mountain View for a day of 5 interviews.
I cannot disclose the questions but I can say that they did not include any Fermi type problems and I felt the questions were very fair and reflected the TPM position I was interviewing for.