College Board
http://sat.collegeboard.org/register
The College Board; online registration for SAT Reasoning and Subject Test.
Practice for the SAT
http://sat.collegeboard.org/practice/
Practice test, daily questions and more for the SAT.
ACT
Online registration for the ACT test.
Practice for the ACT
http://www.actstudent.org/testprep/index.html
Practice test, daily questions and more for the ACT.