I applied online. The process took 3 days. I interviewed at UC San Francisco (San Francisco, CA) in Jan 2012
Interview
First submit application, if selected, you will be interviewed. About 50% of interviewed get ultimately accepted. Mostly judged based on interviews with various faculty - experiences may vary depending on faculty member.
Interview questions [1]
Question 1
They mostly care about whether you understand your previous research experiences and can think about the research they are looking into.