what is the difference between SAT and ACT?

Question

Also, what is PSAT?

Answer 1

Three letters, the S, the P and the C. I wouldn't know.

Answer 2

What is the PSAT?

The PSAT is a preliminary version of the SAT, which serves as an invaluable practice opportunity—and can open the door to National Merit Scholarships and other awards.
Who should take the PSAT?

Sophomores looking to get an early start and juniors who want extended preparation for the SAT should prepare for the upcoming October PSAT.

What is the SAT?

The SAT is a standardized paper-and-pencil test administered by The College Board that measures your critical thinking skills. It tests your ability to analyze and solve problems in math, critical reading, and writing.
Who should take the SAT?

Juniors and Seniors. Most high school students take the SAT for the first time in the Spring of their Junior year. This gives them enough time to re-take the test again during the Fall of their Senior year if they aren't satisfied with their score.

The ACT® test assesses high school students' general educational development and their ability to complete college-level work.

* The multiple-choice tests cover four skill areas: English, mathematics, reading, and science.
* The Writing Test, which is optional, measures skill in planning and writing a short essay.

Answer 3

for complete comparison between both see
http://www.princetonreview.com/college/testprep/testprep.asp?TPRPAGE=141&type=ACT-LEARN

PSAT/NMSQT stands for Preliminary SAT/National Merit Scholarship Qualifying Test. It's a standardized test that provides firsthand practice for the SAT Reasoning Test™. It also gives you a chance to enter National Merit Scholarship Corporation (NMSC) scholarship programs.

The PSAT/NMSQT measures:

critical reading skills
math problem-solving skills
writing skills
You have developed these skills over many years, both in and out of school. This test doesn't require you to recall specific facts from your classes.

The most common reasons for taking the PSAT/NMSQT are:

to receive feedback on your strengths and weaknesses on skills necessary for college study. You can then focus your preparation on those areas that could most benefit from additional study or practice.
to see how your performance on an admissions test might compare with that of others applying to college.
to enter the competition for scholarships from the National Merit Scholarship Corporation (grade 11).
to help prepare for the SAT. You can become familiar with the kinds of questions and the exact directions you will see on the SAT.

Answer 4

http://en.wikipedia.org/wiki/SAT
http://en.wikipedia.org/wiki/PSAT
http://en.wikipedia.org/wiki/ACT_%28examination%29