Khan Academy has partnered with the Law Scool Admission Council to create official free test prep materials for the LSAT. This can be a good starting point with some actual past LSATs and practice questions. Because it uses real exam questions from previous LSATs and is free, it is a good starting point to see if you would like to focus your studying as you move on to more materials.
Powerscore is a great resource for LSAT Prep. Their LSAT Bible Trilogy is probably one of, if not the most popular resource for studying Analytical Reasoning, Logical Reasoning, and Reading Comprehension on the LSAT.
The LSAT subreddit is another community good for commiserating with fellow test takers and the occasional question about why the answer to Question 9 was A instead of B on that one practice exam!