To do any legal research a knowledge of the four forms of law:  Constitutional law, Statute law, Administrative law and Case law, is essential.  “Legal research” consists of tracing the history of constitutions, statutes, court cases, and administrative regulations - looking for connections between them, and making interpretations and judgments of them.

1. Constitutional Law:  Constitutions provide the framework for the functioning of governments.  They also create the “legislative body” that governs a country or state.  The United States Constitution created the United States Congress, and the Washington Constitution created the Washington State Legislature.
2. Statute Law:  Statute laws, or acts, are passed by the legislative body: Congress or the State Legislature and signed by the executive: the President or the Governor.
3. Administrative Law:  The rules, regulations, licenses and decisions made by administrative agencies that operate under the executive.
4. Case Law:  When two parties disagree about what a law means, they ask a court to make a decision as to what is the proper interpretation of the law.

US Courts:

http://www.uscourts.gov/

Find your local federal court, understand the difference between federal and state courts, and link to the Supreme Court, U.S. Court of Appeals, U.S. District Courts, and U.S. Bankruptcy Courts.

US Department of Labor:  Elaws

http://www.dol.gov/elaws/

The elaws Advisors are interactive e-tools that provide easy-to-understand information about a number of federal employment laws. Each Advisor simulates the interaction you might have with an employment law expert. It asks questions and provides answers based on responses given.

• Web Guide to U.S. Supreme Court Research: Gail Partin's thorough and up-to-date guide provides annotated links to the most reliable, substantive sites for U.S. Supreme Court research. The focus is predominately on information that is freely or inexpensively available on the Internet.
• American Law Sources Online (ALSO!): describes itself as "a comprehensive, uniform, and useful compilation of links to freely accessible online sources of legal information for the United States and Canada." Also includes a link to the Mexican Instito de Investigaciones Juridicas, which provides links to online legal sources for Mexico.
• FindLaw: This is the first-stop, premier law resource on the Web. It features a legal subject index, access to cases and codes, information about law schools, law reviews, and legal associations and organizations.
• U.S Government Information (GovInfo) Service of the United States Government Publishing Office (GPO).
• lexisONE: This free site from Lexis-Nexis offers U.S. Supreme Court cases from 1790 and selected federal and state cases from January 1,1997; legal forms; links to more than 20,000 law-related Web sites organized into 36 practice areas, such as communications, constitutional, civil rights, education, Indian & tribal, international, international trade law; and much more. This site won the 2002 CODIE Award for “Best Online Professional Reference Product or Service.”
• Legal Information Institute at Cornell University: Find state laws, federal laws, and laws from around the world. This is the research tool of choice to find the text of laws.
• Law.com: In addition to providing legal application solutions to the legal profession, this commercial site provides free information such the day's top legal headlines, a law dictionary, and specialized resources for legal professionals, law students, business and the public.
• Library of Congress THOMAS: offerings to include Bills, Resolutions, Activity in Congress, Congressional Record, Schedules and Calendars, Committee Information, Presidential Nominations, Treaties, and Government Resources.
• Nolo's Plain-English Law Dictionary:  Free, online law dictionary.
• TheFreeDictionary's Legal Dictionary: Free, online law dictionary.
• Public Library of Law. (PLoL).  Continuously updated free database covering federal law and the laws of all 50 states. Separate portals include Case Law, Statutes, Regulations, Court Rules, Constitutions, and legal forms, which are continuously updated and available by state for a nominal additional fee.
• DRAGNET (Database retrieval access using Google's new electronic technology): Developed by the New York Law School's Mendik Library, this search tool allows the user to find a topic simultaneously in more than 80 legal web sites and databases.  Response is limited to 100 hits; enter specific searches.
• Law Reviews with Online Content: Developed by the New York Law School's Mendik Library, this site provides free online content to 150 law journals. (Most of these are also available through Nexis Uni.)