Most undergraduate programs in the US will require you to take the SAT I (we'll simply call it SAT from now on). The SAT (Scholastic Aptitude Test) is a three-hour multiple-choice standardized examination. It essentially tests your verbal and quantitative skills. The SAT is written and administered by the ETS (Educational Testing Services) under the sponsorship of the College Entrance Examination Board (College Board). Both ETS and the College Board are private non-profit organizations based in the US.
Where do I obtain the Registration Form and the SAT Information Bulletin?