Also, it should be noted that O'Reilly (
http://oreilly.com/ebooks/) is starting to offer a small subset of their books as ebooks in the following formats:
iPhone -- Grab the EPUB and read it in the Stanza App or explore more options here.
Kindle -- Get the Mobipocket file and load it onto your Kindle.
Sony Reader -- EPUBs work well on your Sony Reader.
Computer -- Get either the EPUB or PDF.
Other Mobile Devices -- Explore the EPUB with the mobile version of Bookworm.
I bought a couple of their books, and they look as good as anything in the Sony Store.
I implore those of you with a capable device to pick up a couple of books there. O'Reilly has been slow to adopt ebook devices, because they claim it costs them too much money to back a format that may not be long lived. (and they're right... I'm completely put off by all the different formats and DRM out there)
Tim