Talk about large databases!
Forget millions, WorldConnect gets you more than half a billion records. Just about everyone's family history is reflected here, to some degree, so certainly pay a visit to this powerful and free genealogical search tool.
WorldConnect is a collection of family tree information that follow the GEDCOM format -- Genealogical Data Communications. GEDCOM allows family tree data from different systems to 'talk' to one another through a common format.
The format was developed by the Mormon Church (the folks who brought you FamilySearch), and WorldConnect is housed at Rootsweb, which is run by Ancestry.com. This may well be Ancestry's largest database, but unlike its other, subscription-based resources, you can access this data at no charge.
Searching is easy. Just be sure to use the actual WorldConnect search boxes, rather than searching at the advertised sites on the page, which also have First Name/Last Name search boxes.
A piece of George Washington's family history
Visit the main page of Free Genealogical Tools for more information. And don't forget to also check for your family history at Ancestry.com and NewspaperArchive.com. These are subscription databases, but they are among the most powerful research tools available for looking into family roots.