Google Scholar offers an extensive database of state and federal cases, including:
U.S. Supreme Court Opinions
U.S. Federal District, Appellate, Tax, and Bankruptcy Court Opinions
U.S. State Appellate and Supreme Court Opinions
Scholarly articles, papers, and reports
Patents: U.S. Patents; European Patent Office and World Intellectual Property Organization (WIPO) Patents
To get started, click on the link above, select the “case law” radio button, and choose your search terms. You may click on the menu button at the top left-hand side of the screen (that resembles three stacked horizontal lines) to pull up an advanced search feature that will let you search for a phrase, exclude results with certain terms, etc. You may also search by entering a citation to a case in the search box. After you execute your search, you may use the facets on the left-hand side to narrow your results. One of the most useful facets allows you to narrow by jurisdiction. Select a jurisdiction by clicking “select courts” and then place a check mark next to the courts you would like to search.
If you look to the the top of any opinion's page, you will see a link to the "How Cited" feature. This feature lists other cases in the Google Scholar database that either cite your case or are related to your case. The How Cited feature also provides examples of how these other cases have dealt with your case. While this citator-like feature is a good place to begin your research, and gives an overview of how the case has been treated by other courts, it is not considered to be as authoritative as citators produced by other publishers/subscription resources, such as Shepard's Citations, KeyCite, BCite, and Bad Law Bot.
Legal Research Tutorial
In this short tutorial, Robert Brammer and Barbara Bavis demonstrate how to use Google Scholar to locate case law.