The first place to look for academic e-books is your College library!
In college you can access the collections via the Novell screen/Mulitmedia&Reference/Online Reference/My library icon.
You can also access the libraries e-book collections at home if you have an Athens Password. Please ask in the library for details.
The best (and original) safe site for downloading E-books for free to help with your studies is Project Gutenberg. The majority of content is books whose copyright has ended and so can now be shared freely. Good for classics and English Lit. students.

The Classical Archives has worked with Project Gutenberg previously. If you register (for free) you can download up to 5 pieces each day.

Audio Books for Free is a British run site that also has had links with Project Gutenberg. You need to regsiter for free to download material. Subjects covered include classics, crime, science fiction, humour and even childrensbooks. You can also buy their whole collections in different formats.

The University of Virginia’s Library Etext Centre also makes e-books available for free online. Included in their collection is classic British and American fiction, major authors, children’s literature, American history, Shakespeare and African-American documents.

Cornell University’s arXiv site is a useful resource for Science and Maths students for WBQ/IB/HE. Find full text articles for free on topics including Physics, Mathematics, Computer Science, Quantitative Biology and Statistics.

If you have the latest version of Adobe Acrobat Reader you can get PDF books for free as well! Books in stock are mostly classics with some IT titles available too. Again, would be useful for English students.

A useful gateway site to finding other online e-book sites is E-Books AU. This is not hosted by an educational institution, but many of the links are useful and live.
Remember – you may have to register with a site before they will allow you to download material.