| The ACT is a standardized test. It is over 3 hours long, 215 multiple-choice questions, requires a #2 pencil, and can be important to getting into a more competitive college. It is similiar to the SAT in terms of questions and what's tested, but not the same. I like it because I found it easier than the SAT, but I hated how they made the multiple choice bubbles smaller!
Most schools on the Western Coast of the US (notably California) accept it, most Ivy League schools do, but a lot of smaller colleges and international ones demand an SAT score instead. Pity.
The ACT is divided into 4 sections.
Each section is scored on a scale of 1 to 36. Most colleges really want the combined composite score, though. Unlike the SAT, there is NO penalty for guessing, so don't ever leave any answer blank, even if you didn't read the question. Most people score within 17-23. The scores are on a grade curve. A guidance counsellor can tell you what an ACT Score can be translated to on the SAT score scale.
Getting 90% of the questions right gives you a composite score of 31, about 99th percentile.
Getting 75% of the questions right gives you a composite score of 26, about 90th percentile.
Getting 63% of the questions right gives you a composite score of 23, about 76th percentile.
Getting 53% of the questions right gives you a composite score of 20, about 54th percentile.
Getting 43% of the questions right gives you a composite score of 17, about 28th percentile.
Here's a cool tidbit: If you work on only half of the questions and get those all right, and guess for the rest, you'd probably get a composite score of 23 of 36, putting you roughly in the top quarter (quartile?) of everyone who takes the test. You could blindly guess, or cross off one or 2 possible answers to better your odds.
The English Section involves reading various sentences and figuring out what part needs to be changed, if at all. Very similiar to the PSAT or SAT II: Writing. You read a few passages, and determine whether to change what's underlined, or omit it. Some questions involve whether to add a sentence, and for what reason. If the sentence sounds correct to your ears, it usually is. It's about 45 minutes, and there are 75 questions. If you run out of time, spend the last minute guessing and filling in the blanks.
The Math section is similiar to the SAT, but I'd say more difficult, but more geared to higher levels such as Sequential 3, Course 3, or Math C and what approaches precalculus math. You don't need to use a calculator, and some (most?) graphing calculators like the TI-89 are prohibited. A scientific or 4 function calculator works just fine. You don't need a calculator, but it could slow you down for simple multiplication questions. It is 60 questions, and you have 60 minutes.
The Reading Section is similiar to the SAT. You read a passage, and answer questions about it. What does the writer think of this, in line 24 what does he/she mean by "my way", what is the main idea of the essay? It's only passages, and you have 40 questions, 35 minutes.
The Science Section is probably easier than you think. You don't need to know Physics or AP Chemistry , but you need to be able to read graphs, and to some science reasoning. You'll see an experiment, and asked questions with the information in front of you. One sample question dealt with the migration of squirrels and four possible theories. "Does theory 1 contradict theory 2?" 40 questions, 35 minutes.
Seriously, one of the best ways to prepare is to get a sample ACT and practice. Most high schools will freely give out copies, or you could send away for one, with a CD. Or you could buy a test-prep novel at your local bookstore. I'd reccomend Princeton, I've heard stories about Kaplan. I took a review class at my high school, but they have private tutors availible in some places. Or you could /msg me and pay me $50 an hour.
Check out act.org for trivial things like registration and test prep. | 
