i do IT work, and the "it" thing these days is to throw the occasional probability question out there. The last time i stumbled on this, i'd just sat the GMAT and had probability somewhat down... still, it is the one region in maths that has always left me the most confounded.
I have not stumbled across any killer probability books either - but i am sure they exist! Or lecture notes/something online?
UPDATE: i did hons maths pricing black-scholes etc back in uni (10 years ago), so i'm not shabby (but also def not brilliant) at maths. So that's me. As for the questions in particular, you know, a good book that started at the beginning (simple coin toss stuff) and then rocketed off to at least P implies A, with a thorough set of questions and answers would be good. Does that help?