The "Download Now" link directs you to the iTunes App Store, where you must continue the download process. You must have iTunes installed in order to open the link, and you must have an active iTunes account to download the application. This download may not be available in some countries.
From The Mermaid Inn:
Much like wine, the flavor of oysters changes based on weather, region and method of cultivation. Oysterpedia, created by The Mermaid Inn restaurants in NYC, was designed to take the guesswork out of ordering oysters as well as to provide a reference tool for the oysters you have already tried. This application will teach you the difference between a Bluepoint and a Kumomoto and give you the flavor, size, location, photos and notes of over 200 oysters from the coasts of North America. You can also rate the oysters you have eaten and save them in My Oysters. The next time you go for seafood, you can reference the list of oysters you have already tried and either re-order the ones you like or you can be adventurous and continually experiment with new ones. As you try new and different oysters, you will realize that no two oysters are alike. Enjoy.