Scholarships.com (http://www.scholarships.com/)
Create a profile, including your accomplishments in academics, atheltics, etc. Their searches also can help you choose which colleges to look at, and get matched up with scholarship opportunities. Free.

Fasweb (http://www.fastweb.com/).
Another great site, Fasweb offers a similar database search function, although it is more popular and has a lot of useful information. I can't say 'Free' enough times.

CollegeToolKit.com (http://www.collegetoolkit.com/)
This less-trafficked site has a more extensive set of resources to help students with the whole college picture. They also offer direct access to scholarship online applications. Also free, it is worth checking out.