Celestial Lands Library
Philosophy Archives Section
(We cannot have the comprehensive library on Philosophy that we would love to have, but luckily, we don't have to. There are plenty of other places where you can find the ideas, inspiration, and thought behind Liberal Religion. Here are but a few of them)
Project Gutenberg -- This is an excellent resource, because people like you have made it so. It is a collection of online works, both of philosophy, history, and literature, made electronic and submitted by people around the world. You will find much worth reading here, and it is all free.
The Internet Classics Archive -- This is a great site, supported by MIT, that is one of the greatest online collections of classical literature and philosophy. They are working through some technical problems, but the works are all there, just a little harder to access. So you have to work a little for your free works.
literature.org -- This is a bare bones online collection, both of classic philosophy and fiction, sponsored by Knowledge Matters Ltd. It is a good place for reading online.