Letters of Recommendation are submitted through LSAC via the Credential Assembly Service (CAS), specifically called LOR (Letter of Recommendation Service). You should have prepared, on average, two letters (from PhD faculty), on professional letterhead, sent directly to LSAC.
When asking for letters, make sure you are the considerate, professional lawyer to aim to become; make an appointment to meet with letter writers well in advance of the application deadline. Ask them, "Do you feel you know my work well enough to write a positive letter on behalf of my application to law school?"
Provide information about your background to assist him/her in writing a detailed letter:
Waive your right of access since you may find writers unwilling to write letters if applicants have access to them, and some admissions committee members may discount disclosed letters. If you have not been notified that your application is complete by about one month before a deadline, speak with those writers who have not sent letters yet to remind them politely of the approaching deadline. After you have received decisions, send thank-you letters to your recommenders, and let them know where you have been accepted and where you intend to enroll.
Recommenders send letters directly to the CAS, which then forwards up to four letters to law schools to which you are applying. You can specify that targeted letters be sent to specific schools; otherwise, general letters will be sent to every school to which you apply. Letters will be maintained for five years from the time you register for CAS or from the time you take the LSAT, whichever comes last.
To read more on letters please visit: http://www.lsac.org/llm/applying/llm-letters-of-recommendation.asp