Not only can you now [pre-order][ippo] or [reserve][ipr] the iPad, Apple has updated their site with some fresh info about the device.
The biggest news is about the iBooks app: yes, it will support DRM-free ePub books from any publisher, meaning tech books from O'Reilly and the Pragmatic Programmers, as well as a vast selection of public domain works, will be usable on day one. iBooks can also use the iPad's VoiceOver technology to read books to you aloud, a feature that sparked a huge controversy when Amazon added it to the Kindle.
Also, the Photos app will support RAW-format images, that you'd probably load onto the device using Apple's not-yet-for-sale Camera Connection Kit. The possibility of stashing some of the many GBs of RAW photos I've taken on the 64-gig iPad I just ordered has me very, very excited.