Wowio is a free web based service that allows you to download books, magazines and graphic novels. It gives folks an opportunity to catch up on the classics like Two Gentlemen of Verona or discover classic comics/graphic strips like Steve Canyon by Milton Caniff.
They have books in wide variety of categories such as Arts and Design, Philosophy, Business and you can't have too many Science Fiction and Fantasy books as far as I'm concerned. The books are in the Adobe PDF format.
There is a daily download limit of three books a day but how fast can you read on the screen anyway? It is free but you do have to register and they ask you not to pass the books around to other folks.
I've read a few and they are not bad. The main problem is having the time to read what I've downloaded before I grab a few more. It is an interesting idea and I hope that it will grown and develop.