There's now an Amazon press release which describes the device and says it's available at http://amazon.com/kindle. That page has several video demos including a "drop test".
PaidContent has a quick review: First Look: Amazon's Kindle Reader: The Gap Between Description and The Device.
Boing Boing has 15 Things I Just Learned About the Amazon Kindle, which includes information about file formats and the DRM (Digital Rights management). Kindle has a web browser, can play MP3 files, but can't read PDFs. The 16th thing is: "Having copied over .DOC, .TXT, .RTF, .PDF, .GIF, .JPEG, and .PDB files directly to the Kindle via USB, only the .TXT file showed up for viewing."
For background, see Amazon will launch Kindle ebook reader on Monday and Kindle -- the Amazon launch, both below.