ACT, Inc.
http://www.actstudent.org
Official student site for ACT test-takers. Set up an account to register, send scores, etc.

ACT Test Prep
www.princetonreview.com/college/act-test-preparation.aspx
Free practice tools and much more.

LearningXpress Library
http://www.oplin.org/tests
Click on College Preparation (on the left hand side) to get to practice exams for the SAT and ACT.  This site can also be accessed via the Electronic Resources link from the Library's home page.

SAT

SAT
http://sat.collegeboard.com/home
Register and prepare for the SAT.

SAT/PSAT Test Prep
www.princetonreview.com/college/sat-psat-test-preparation.aspx