If I buy that one and download books, is it possible that sharing with ipod kindle, PC and Mac?

There are some cheaper ones on amazon that I am thinking of purchasing simply for my 500-600 PDF books, articles, reports, etc.
So I have no need to access the internet/wifi, and no interest in doing so. Is there a way to shut it off decide I decide to purchase one?
Or, is there something like that product which is simply used for reading PDF documents?

I would appreciate hearing from anyone who has purchased a wireless reading device like Amazon’s Kindle or Sony’s Wireless Reader. Or, perhaps someone has another wireless reading device.
I’d like to know how you would rate the wireless reading device that you have.

I was wondering if i could carry around the small transportable Kindle Wireless Reading Device at school.
Do they sell the book “The Earth And It’s Peoples- A Global History Second Edition” for history on it?
So i could carry less around at school
Thanks

Is it worth it?? Are good books available?? Is there somewhere I can look at a list of what book are available??
What is your overall opinion of it??