Collegeboard is in charge of both.
If you are taking both tests invest in the separate books, the question format for SAT IIs and AP exams are different and the information on each test may not be exactly comparable
The AP exams are usually offered over two weeks in the first half of May. You can find the schedules and dates for specific exams at the College Board's website at http://professionals.collegeboard.com/testing/ap/about/dates .
Take all the major sciences -- physics, bio, chem -- and all the math you can handle. Take AP classes, if your school offers them. Sit for the AP exams and the SAT-II subject tests.
Yes, mechanical pencils are allowed on AP exams as long as they meet the College Board's guidelines for acceptable writing instruments.
Study
AP stands for Advanced Placement, and is a branch of the College Board franchise (same corporation that does SAT, etc.). AP Classes are college level classes that high school students may take, pass an exam for, and receive college credit for. AP exams are scored on a scale of 1-5 (1=Fail, 5=Highly qualified). Most universities accept a 3 or above for credit.
You are eligible to take an AP exam without having taken the AP course. You must thoroughly prepare on your own.
The website collegeboard dot com has detailed information about SAT exams, including the exam dates and fees. You can also use it to register for a SAT and to submit and view your SAT scores online.
yes
Matching
SAT exams are given at testing locations in many different areas which are often schools. To find the nearest testing location and register to take an SAT exam, you can visit the website at http://sat.collegeboard.org/home
The collegeboard website has a store where you can buy any of the released old AP exams. I'm not sure where you can do it for free.