where can i read books online for free?

Try http://www.gutenberg.org for free, full-text, out of copyright books.

Hope this helps.

See if your public library has ebooks. That would be legal. Ebooks are only legal if they are out of copyright or have the permission of the author.

Stay away from peer sharing sites that steal from authors. They may also have viruses.

Lots of legal sites listed here

Millions of Free eBooks and Audio Books Online
http://www.techsupportalert.com/free-ebooks-audio-books

Amazon,com has over 270,000 free books that you can read on your PC by downloading the free kindle pc app.

I don't know if you like classics or not. If not, these are useless and disregard them. Because of copyrights and all that, it's hard to get modern books for free, but classic sites abound. Here are two that I use:

http://www.bibliomania.com/
http://www.classicreader.com/

Fictionpress.com. It's a website full of stories written by authors...no actual books like "Harry Potter", but there are good stories up there.

If you have iphone or ipad, try the ibook app.

if you're into manga :mangago.com has lots of magas that you can read online and it's free.