When a case has been reversed or overruled, it is considered "bad law" and should not be cited as precedent. Use "Shepard's Citations" in the LexisNexis Academic Universe database to determine whether a case remains "good law." Refer to the diagram on the Courts and Case Law tab. Select Legal and click on "Shepard's Citations." Type in the case citation. Shepard's will list other cases that have cited the case, as well as the history of the case within the court system.
For more information about updating legal resources in general and using Shepard's Citations in particular, please refer to the American Association of Law Libraries' "Public Law Toolkit - Updating"