Spark Notes: Find sample questions, message boards, an online book and a section that explains how the ACT works.

Study Guide Zone: This site offers free sample questions and answers and tons of study tips to help you do your best on the test. Download a free study guide here.

Official ACT website: This is a comprehensive site complete with sample questions, career planning, college information and a student blog. You can even check your scores after you've taken the test here.

The Blue Book of Grammar and Punctuation: This site provides free interactive quizzes to test your knowledge of grammar and punctuation.