There are plenty of search engines on the web for ebooks. Neotake is a search engine for ebooks that offers a couple of extras. Neotake provides the option to become a member (free registration) of a community that ranks and reviews ebooks. Registered members can also network with other readers.

To make searching for ebooks a little bit easier, Neotake offers a browser plugin for Firefox, Chrome, and Internet Explorer. The browser plugin allows users to search for ebooks without having to open Neotake in a separate browser window.

Thanks to Steven Anderson for the lead to Neotake.

If you’re in need of some new reading materials for your classes, but you don’t have money to spend on new books, search for some free ebooks on Neotake.

Here are some related items that may be of interest to you:
Seven Places to Find Free eBooks
Audio Owl – Hundreds of Free Audio Books 
Free Audio Books from Books Should Be Free