Since I got my e-reader, then I started collecting free download classic e-book..:)
This is some of the source:
1. Project Gutenberg http://www.gutenberg.org/wiki/Main_Page
2. Girlebooks http://girlebooks.com/ebook-catalog/tag/free-ebooks
3. Open Library http://openlibrary.org/
4. Planet E-books http://www.planetebook.com/free-ebooks.asp
5. Obooko http://www.obooko.com/index.html