In case you see the cheat sheet and think, "Wow, I'd love to understand that," there's an excellent (albeit challenging) complete course on machine learning in Stanford's "engineering everywhere" online repository. http://see.stanford.edu/see/courseinfo.aspx?coll=348ca38a-3a...
Another option is "Programming Collective Intelligence," by Toby Segaran. I read through it recently on a long flight to Australia. It's one of the most straight-forward AI books out there, presenting most of these algorithms in just a few pages with nice sample Python code and diagrams. A perfect intro/refresher, and it takes a web developer perspective on these techniques.
Since reading it I've noticed how many friends have it on their bookshelves.
While it does a great job of explaining many AI concepts in an unintimidating fashion, the Python code in it is rather buggy. On the balance, I'd still recommend it as an intro.
