Check out the Web Links, eBooks section.

For a start though, you can also have a look at the E-Book Uploads section from mobilread.com.

Google has also a book-search page. Check it out at the Google Book Search Interface

baencd has quite lots of free eBooks too. Check it out.

for the SciFi Fans out there - check out the following links:
http://www.suvudu.com/freelibrary/
http://craphound.com/novels.php
http://www.sc2.com/e-books/
http://www.ebookmall.com/categories/CATID35.htm
Especially - check out http://baencd.thefifthimperium.com/ - they have some promotional CD' s with really great stuff !!!
http://www.epubbooks.com
http://www.smashwords.com/ - Some free books here.

Some authors do put some of their eBooks online for free. This is a list of known sites - small so far, but maybe it will grow with time.

• Science Fiction - Jeffrey A. Carver (English)
• Science Fiction - Steve Jordan (English)
• Bizarre Stories - Collin Landis (English)