Applying to law school in the U.S. is now centralized through the Law School Admission Council (LSAC), the organization that also administers the Law School Admission Test (LSAT) that most law school applicants are required to take. Applicants need to file only one application and supporting documentation that will be made by available by LSAC to those law schools to which you have applied. Below is a link to the LSAC.
For a variety of reasons enrollments in law schools have been down in the past two years, at least (as of Fall 2014). For this reason, law schools have stepped up recruiting efforts and now may bean ideal time to apply if you are thinking of a career in the law or some allied field where a law degree will be useful. Below is a link to an article that talks about this.