Amazon is offering an eBook. Dozens of companies lost their shirts with ebooks in the late nineties. Back then, laptops were expensive and PDAs had tiny screens and were hard to read (Apple's Newton was the exception). So many thought that ebooks--light, portable readers--would catch on. But the number of titles available for any given platform were limited, and too many manufacturers opted for proprietary book formats that made publishing a nightmare. A successful book might have to be made available in several different formats. At least one company (I can't remember the name) had the good sense to adopt PDF as the file format, but nonetheless, ebooks never really caught on.
File formats were just part of the problem. There was also digital rights management, the mechanics of buying, downloading, and installling the files was another, battery life was yet another issue, finally, some were awkward to use. It's hard to beat books, which have had hundreds of years of design packed into the format.
Amazon's design has a keyboard (for taking notes, which was usually impossible with earlier ebook systems), probably uses e-ink, which extends battery life, and comes with EVDO wireless, meaning you can download books easily and probably also does email and other common chores.
It will be interesting to see how this does. If Amazon can afford to play the "give away the razor, make money on the blades" game and sell it cheap with the hope of making it up on book sales, it could catch on--if the books are cheap enough.
Despite the popularity of online music sites like iTunes, music prices did not come down any because music publishing houses were and still are greedy--they want all the money they used to make on CD sales, but they no longer have any distribution costs. If book publishers take the same route, Amazon may have tough sledding. And if it is hard for authors and publishers to prepare a manuscript for the ebook, it may be even worse.
Having said all that, I think ebooks are inevitable. A lot of books are read once and discarded, and many technical books have time sensitive material that becomes less useful in just a year or two. And the high cost of college textbooks could be brought down with cheap ebooks. So we will have ebooks; what is uncertain is what platform we will read them on. Most of us don't want both a laptop and a second ebook "thing." We'd rather have a single device that serves as both, and a tablet computer would do nicely.