SermonAudio.com - this is a terrific site that is chalk full of quality sermons from all sides of fundamentalism and conservative evangelicalism. I probably download and listen to 5 - 10 hours of sermons from here every week. You can search for sermons by passage, speaker, topic, or date. There are thousands of sermons there covering about everything.
Christianaudio.com is another favorite. They offer thousands of titles of books - but you have to pay to download them. However, each month they offer one book for free. It's the only time they will ever offer that book and they offer some great free titles every now and again. I've donwloaded David Brainard's diaries as well as Confessions of the Reformed Church (containing the Augsburg and Westminster Confessions amongst others). If you like audio books, this is a great site....if you like free audio books, it's an even better site! Well, at least once a month! Enjoy!