Via TMN comes news of a page that does exactly what it says on its headline 17 Sensational, Free and Downloadable Graphic Novels. I've not really read anything on here, but Sandman and Y: The Last Man are both highly regarded (and I've downloaded them for later perusal). I have though read a later edition of Sandman and some other Neil Gaiman stuff so if the rest of the freebies here are of that standard then there's some worthwhile reading here.
One thing. You can get more freebies on a link from the Sandman page. If you go here, Vertigo have a catalogue of what looks like their whole range, and those with a "#1" next to them have downloadable first issues and there are any number of well regarded (again, I've not actually read but I know them by repute) comics including The Invisibles and Preacher. So now's my, and your, chance to find out if these things are any good.