PSAT and SAT/ACT student test preparation websites:
The Khan Academy offers full-length practice tests for the PSAT/NMSQT which can be taken on paper. NMSQT stands for the National Merit Scholarship Qualifying test. This can help you get scholarships not only through the National Merit Scholarship program, but also helps gain access to scholarships to colleges throughout the country!
Here are some sample questions offered by The College Board, creator of the PSAT and SAT tests.
SAT Test Prep:
The Khan Academy works closely with the College Board, providing this free SAT prep program. Also, they have a full length practice test. Click the link below for it:
SAT, PSAT/NMSQT, ACT Practice Tests:
Actually has just about every practice test needed, including the ASVAB. There are AP practice tests as well as those listed above, and SAT subject tests as well.
Here is another site that has every practice test imaginable.
Has links to every AP Practice Test.
Helpful information about the ACT.