This is something that I might actually use quite a lot — but it looks like that the wireless Whispernet is based on the US Sprint network, and thus this reader will not be available for Europe, not at least for now. See: Amazon.com: Kindle: Amazon’s New Wireless Reading Device: Kindle Store.
frans goes blog 
I think it is, indeed, a very interesting device. I would be definitely interested in buying it.
It could bring a revolution (I don’t say that because I’m French) in academic research, as you can select entries directly in the text and so forth.
I’m looking forward to seeing it released in our continent, but I’m quite sure that we’ll have to get a dodgy contract with a power-abuse phone company to have access to it!
Wait and see!