aha looks like Amazon are playing both sides of the fence, they said they’d offer the Kindle services in non-Kindle devices, but I don’t think anyone expected it to be so soon.
The iPhone app is free, so saves you forking out $360 for a Kindle, it can access all of the eBook content available on Amazon (although strangely you cannot do this through the application itself, you have to use the web browser), the application then copies the files from your account. A terrific feature named Whispersync, keeps your current location in a book in sync with the Amazon servers, so those that own a Kindle can keep both in sync, including notes. Unfortunately it only reads Amazon’s proprietary formats and is limited to North America, but without having to worry about a hardware distribution chain for the iPhone app, this may be a simple way for Amazon to spread their Kindle market share worldwide, let’s hope so!
more info here: