The app became available last night. According to the description, these are the additional iPad features:
New beautiful user interface tailored to the size, look and feel of the iPad
New Home library view with pinch, zoom and scrolling support
New page turning animation that replicates the look of turning a page in a book. Customers who prefer a simpler, unadorned reading experience can use the default “Basic Reading Mode” option to turn off animation
Adjustable screen brightness within the app to help reduce eye strain
This initial Kindle for iPad release has only been tested on the official iPad simulator provided by Apple.
TheNextWeb.com feels that the iPad Kindle app “puts standard Kindle to shame.”