The Free Application for Federal Student Aid (FAFSA) is the hub for applying for federal funding for college. This is usually required by all colleges and universities who receive and disperse federal monies for college students. The FAFSA is generally submitted by February 1st in the student's senior year. Current college students have a later deadline--usually March or April.
This organization monitors high education testing practices and provides a comprehensive list of colleges in the US that are test-optional.