If you are looking for legal and free eBooks with the copyright expired, take a look at Project Gutenberg.
The Gutenberg is working on collecting all texts out of copyright, they have more than 25.000 ebooks in the library. They can be downloaded individually, or in collections as DVD or CD-ROM images.They can be found here.
The DVD from July 2007 has about 17.000 titles, most of what was completed at the time.
For SciFi fans there is a CD-ROM for download. Look at the link above.As far as I know there is *some* modern SciFi stories from people like Cory Doctorow who have released them under a Creative Commons License.Most of the titles, however, are more than 70 years old. One story that I actually downloaded and read on my iPod Touch was Robert Louis Stevenson’s “Strange Case of Dr.Jekyll and Mr. Hyde”. Having seen the BBC series by Steven Moffat I wanted to read the original story and downloaded and read it.
So, if you are looking for classic old stories, go there. You can most likely find it.