I generally get innundated with request from my friends for e-books as you can quickly consult 4-5 books on a given topic as well as save paper.The files come in two formats: CHM and PDF.
CHM files are basically bundled HTML files and can be extracted to plain HTML.
PDF files are best viewed in Foxit Reader
Surfing today, I came upon this nice website http://www.flazx.com
that hosts a variety of such ebooks.
My request to all subsequent users, please do purchase the original print version, if you find the book useful as it then helps both you and the publisher (and subsequently, the author).