I applied online. The process took 1 week. I interviewed at Jane Street (London, England) in Dec 2012
Interview
Had two phone interviews. Passed first one comfortably then lasted about 40 minutes in the 2nd round before getting stumped on a question. It's pretty much the case that you have to nail every question to progress further.
Interview questions [1]
Question 1
You are going to see a sports tournament between two teams. Best of 7. Can only have win/loss outcomes. Devise the optimum betting strategy such that at the end of the tournament you are either up 100 or down 100.
Was initially confused about starting money but he told me that you can bet any amount.