Each law school has its own distinct admissions process, including its own form and often its own deadlines. The student will therefore want to contact each law school in which he or she is interested individually and get application materials.
The American Bar Association has placed its List of ABA-Approved Law Schools online, and that list includes links to most of those schools so that you may learn how to contact them.
Another excellent source of information on law schools is the annual Law School Forum, held in major cities around the country, including Chicago, usually in early October. For more information on the Law School Forum, click either on the ABA site above, or the Law School Admission Council site below.
However, the application process has many features in common. For example:
the Law School Admission Test (LSAT) is a requirement for admission at almost all American law schools. It is a nationally standardized half-day examination designed to measure certain mental capabilities important to the study of law. The test is not intended to examine knowledge in a particular specialization, but rather covers a broad range of disciplines. The questions measure the capacity to read, understand, and reason logically using a variety of verbal and quantitative material. There is a written ability section designed to measure skill in using standard written English to express ideas clearly, precisely, and fluently. The Law School Admission Council administers this test, and its web site contains much valuable information.
Virtually every application also requires a written personal statement about yourself and why you want to attend law school. There is even at least one commercial firm online, accepted.com, that will sell you its advice about how to write that statement.