The Judicial Branch is responsible for administering justice and interpreting laws. It is comprised of the Supreme Court and the lower federal court system. Only the Supreme Court was specifically created in the Constitution while the structure of the lower federal court system was left up to Congress. The Supreme Court is the highest court in the United States, ruling on the constitutionality of laws, reviewing finding of lower courts, etc. Unlike the other two branches of the federal government, judges are not elected but rather are appointed by the President with the consent of the Senate, and are appointed for life.
Some useful resources specific to the Judical Branch are:
Cases and Codes. (FindLaw) Contains resources and links for both state and federal laws.
Govinfo.gov - Judicial Publications. (Government Publishing Office) Provides access to selected judicial documents such as judicial publications, court opinions, and independent counsel investigations. Contains official and authenticated publications, with coverage from 2005-present with some documents prior to that.
Supreme Court of the United States. Links to opinions, oral arguments, case documents, etc.
United States Courts. U.S. Supreme Court, Courts of Appeal, District Courts, and Bankruptcy Courts.
Federal Judicial Center (FJC). (Supreme Court of the United States)