eBooks

Hi,

I am looking for a place to buy eBooks. I have seen a lot of the books
I own available for download in CHM format. I do not know if these
ebooks are legit or not (as I got a couple from websites I found via
Google and I highly doubt they are given away for free!) however they
are very well done (proper TOC with bookmarks, etc.).

I was wondering where I can buy books in CHM format from? I can't seem
to find anywhere except places where I can download them for free
(which although it is good for me as I don't have to pay, it isn't all
that good for the authors).

Does anyone know of any good sites I can buy my books from as ebooks?
I own a copy of Programming C# by Jesse Liberty but also downloaded
the CHM as I like to be able to print out each chapter and write notes
on it without defacing the actual book.

Thanks all!