College Board Scholarship Search: Non-profit organization that connects students to a wide variety of college scholarships. You are required to make an account.
Peterson's: Search for scholarships by area of study, ethnicity, religion, disability, and more. No registration is required to search but you must make a Peterson's account to view application details.
Fastweb: Search over 1.5 million scholarships. Requires registration.
Scholarship Search - SallieMae: Search for over 3 million college scholarships. Requires registration that allows you to set alerts and customize your searching.
Scholarships.com: Search scholarships and grants for free. Registration is required to search and set up alerts.