There are easily 50,000 free books online, with a good 10,000 titles that are popular in dead-tree editions.
Many popular magazines are available in e-editions.
But many folks are still hung up by the difficulty of scrolling, rather than flipping, through the latest titles. Handheld computers often have tiny screens, making reading difficult. Dedicated e-book readers tend to be larger. Finally, the contrast of a computer screen doesn't typically approach that of ink on paper. Enter E Ink.