Stanford Machine Learning course
theorymatters.wordpress.com
theorymatters.wordpress.com
However, I come from a Physics background, so the math is just different, and may in fact be easier. However, I've been referencing my Mathematical Methods for Physicists book (Boas) pretty often to brush up on some linear algebra techniques.
Lastly, its been said quite a bit in these forums, but if you are just interested in implementing this stuff, definitely check out Collective Intelligence by Oreilly. I use that book in tandem to bring some of the high-level concepts back down to earth. :)
Good luck
The midterm for CS 229 was probably the hardest exam I took in college.
(I mean, sure, you can try to fire-and-forget, but for the most part you'll either fail with no clue why, or fail to get very good results. Decision trees might be a moderate exception, although even then you really ought to understand how they are constructed and the implications of various choices you can make.)
The obvious example of this is boosting where the theory lagged far behind the experiment - everyone wanted to invent a theory to explain why boosting was so effective.
hey industrialists out there - publish!