SAT II's are also known as subject tests. I think there are Chinese, Writing, History, Biology, Chemistry, Physics and Math, that's all I remember. Each subject test is out of 800. Most private schools (all ivys) require high school students to take the writing SAT II, math and one science.
good luck.
for SAT's, Princeton Review has the best books. Kaplan's books are too easy and Barren's books are too hard. Anyone who's interested in taking the SAT's should try to get Princeton Review's 10 Real SAT's. It helped me a lot.