Below are some resources to help you prep for the ACT. All of these resources have various strengths and offer differing perspectives on strategies and approaches toward test taking. Depending on your learning style you might find some resources more effective than others. Use your critical thinking skills!

ACT Official ACT site. Dates and other important information to register for the ACT.
ACT Test Prep Official test prep website with practice questions and retired tests. Online test preparation course with free (automated) personal tutoring.
Princeton Review Free practice tools from one of the leaders in test preparation.
Kaplan In-depth information about the ACT and strategies to help you prepare for the test.
Kahn academy Short online videos that work through practice problems of old tests
SparkNotes Analysis of each section of the ACT, including specific ACT strategies.