Scientology churches have many tape recorded lectures by L. Ron Hubbard available for the general public to listen to. Mr. Hubbard recorded over 3000 lectures on the subject of life, human thought, our relationship to other life forms and the physical universe.
In addition to his work as the founder of the Scientology religion, L. Ron Hubbard was a prolific author of fiction, an educator and even worked in film.
There are some other good sites on the Church of Scientology:
The Ontario Consultants on Religious Freedom have a Scientology overview and a page about Scientology beliefs and practices.
J. Gordon Melton wrote a book calledthe Church of Scientology, and excerpt of which is up on his web site. There is also a review of this book by Dr. Derek Davis online.
There is an online Press Office for the Church of Scientology International and a site which presents papers by several religious scholars on various aspects of the Scientology religion.