LSAC and the LSDAS Report
    LSAC stands for Law School Admission Council.  The LSAC is an organization that provides various functions; two of which are very important for your purposes.  First, the LSAC administers the LSAT exam.  Second, LSAC compiles the LSDAS reports that are now required by most law schools.
    After looking at a calendar, the next thing you need to do is go to the www.LSAC.org web site and look around.  The LSAC site is the most important place for all of your application details.  The web site provides a wealth of information regarding the admission process.
    The LSAT is the law school equivalent of the MCAT (Medical College Admission Test) for medical school.  While other factors play into admission, for the most part law schools use an applicant's LSAT score and undergraduate GPA (Grade Point Average) to create a single number that they use for admitting purposes.  The majority of the class will be admitted using that number alone.
    LSDAS stands for Law School Data Assembly Service.  LSDAS prepares a report compiled from data you will send them.  The LSDAS report will be put together by LSDAS and, at your request, distributed to the various law schools to which you are applying.  Without an LSDAS report law schools would have to perform all of the housekeeping details, such as undergrad degree confirmation and GPA calculations, in house.  Upon registration with LSDAS, you will be advised of the materials you will need to forward to them such that they can assemble a report to be forwarded to the schools to which you apply. 
    You can register with LSDAS and for the LSAT at the LSAC.org site.