When I interviewed just a couple months ago, it was much the same - tough brain teasers, mental math, and straight up probability questions.
I think if you read all the available info, you can do very well on the brain teasers - "heard on the street", as someone mentioned earlier is a good book, and a few other ones as well - just go on amazon and do a related search. Anyway, they mostly want you to, if not get the right answer, attempt to solve the problem thinking in the right direction.
For the mental math and probability questions - you should get these right 100% (almost) just study up on conditional probability (i.e. Bayes Theorem).