Okay, I'll answer your question. I own a kindle. I won it as a prize for my awesome review-writing skills for Amazon. (I rule). I wouldn't normally buy this sort of thing for myself, being a bit attached to paper books.
But it's actually pretty darned nifty. It is grey-screen only (as was my first computer, actually), but it does more than just read books. You can do some web surfing, though high bandwidth pages load weird, and you can check email. Check out this page
here for some of the stuff it can do. You don't pay for any of it, other than the price of the Kindle and any books you buy. Lots of sites offer free books, and those you don't pay for at all--some other readers charge you every download. Kindle doesn't--only if it's a Kindle book.
It holds an ungodly amount of stuff. The interface is ridiculously simple, so even a technomoron like my mom can use it.
Sometimes pictures are a problem in Kindle editions--if you check the reviews before you buy you can spot those easily.
You can also self-publish on MobiPocket, which allows your stuff to be read via any MobiReader enabled device (blackberries, etc) as well as the Kindle.
It's really small and light, and you're going to probably want a cover for it to keep it protected. (I worry about screens getting scratched though I've never heard anyone complain about it with a Kindle). You can adjust the print size and even have it autoturn pages for you.
The downside to me is that book prices, though most of the time cheaper than paperback, are still not exactly bargain basement. And you can't give the book to someone else when you're done. So if you have friends you like to swap out books with, you can't do it with a Kindle.
Also, if it's a nonfiction book you might have some problems navigating Table of Contents (which is, I admit, a beeyotch to create!) and there's often no access to any sort of book index.
Okay, that was sort of rambly--anything in particular you want to know?
HK, writing exams.