I recently got an invite to Book4Me, and have some invites I can send to other people
Its a really cook free eBook site, it has a LOT of eBook, I've been able to find everything I have searched for so far.
It has academic books, fiction books, non-fiction books, pretty much any genre/category you can think of xD
I've only been a member for a week or so and I love it.
Just post, or send me your email in a PM and I'll send you an invite.
I've got 10 invites left.