Legal sources are divided into two broad categories:
Primary sources include laws and statutes, court decisions (case law), regulations, constitutions and other documents published by some government authority (such as judges, presidents, and legislatures).
Secondary sources are journal and magazine articles, websites, and encyclopedias that comment on and analyze the law.
Primary sources are the law and secondary sources are about the law.
The type of information you need determines where you should begin your research. Most likely you will need to use both, but it's often best to start your research with secondary sources, especially if you just have a legal topic in mind, but not a specific case or legal citation.
Judicial Law (Case law, court decisions and opinions)
Statutory Law (legislation, statutes)
Administrative Law (Codes, Regulations, Exective Orders)
Use these to find articles from law reviews and journals, legal encyclopedias, and newspapers.
These are just a few of the many websites with free legal information.