The U.S. Department of Education administrates Federal education policy. They do many things, including create regulations to implement certain laws, offer guidance on complying with those regualtions, collect data on U.S. education, and investigate allegations of non-compliance with Federal law.
When researching Federal laws pertaining to education, you will frequently come across these Acts:
As these Acts have been amended several times, the best place to start your research is an annotated code, like the United States Code Annotated or the United States Code Service. Both of these have a popular name table, which will show where the laws have been codified, and you can use that to find the most recent version of the law.
You can find education law cases at every level of the Federal Court system - District Courts, Circuit Courts, and the Supreme Court. When searching for cases, consider which courts' opinions are binding authority in your jurisdiction.
Search terms are going to be based on your particular issue and fact pattern. You will want to consider facts like the level of the school (i.e. elementary, secondary), the funding of the school (i.e. public, private) and the role of the people involved (i.e. student, teacher, administrator)
Using the West Key Number System, you can look at topic number 141E for education.