California Department of Education STAR test prep: Find here printable sets of released test questions from 2003-2008. Each set is representative of the various content areas measured, grades 2-11.
Learning Express Library's "School Center" database: Offers practice tests, exercises, skill-building courses and eBooks across content areas. This site requires users to *register, and is geared to the student or class who desires to prep for a test digitally/online (though each of the pages can be printed). To take a test online (i.e. using a computer), the regisitered student adds the test to his/her "Center" and then proceeds to take the test. Upon completion, the student clicks a button and the test is automatically scored and saved per student. Students can go back to find answers and solutions to problems they missed. This site best suits upper elementary (especially 4th grade), middle school (and especially 8th grade) and high school students.
*Note regarding registration:
"User name"= student's library card number
"Password"= student creates his/her own password