You can sign up to be notified when Kindle for Windows Phone 7 will be available.

While Microsoft's share of the smartphone market has shrunk in recent months, that won't stop Amazon from putting out a Kindle app for Windows Phone 7 users later this year. Amazon says the app "is optimized for the unique user interface of Windows Phone 7," and will include the company's WhisperSync technology, which syncs the last page you read as you switch between devices.

It's not exactly clear when the app will arrive, but Windows Phone 7 smartphones are hitting the market now, so it probably won't be that long. You can sign up at Amazon's Kindle for Windows Phone 7 page to be notified when the app is available.