There is quite a bit of cool public domain material around, I thought I'd start a bit of a list.
- Internet Archive
- A huge range of resources here. Can be a bit of a challenge to wade through, but has media of every type, and playing around with the advanced search can reveal some gems.
- Project Gutenberg
- Project aiming to make free ebooks available for works that have expired copyright or are public domain. Some of the ebooks have different usage rules.