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 Cory Bohon:
The free, lite, ad-supported version of the popular Coin Flipper Pro ($0.99). If you're looking for a version without ads, check out Coin Flipper Pro. ----------- Never be without a coin to flip again! The Coin Flipper application for iPhone, iPod touch, or iPad will let you flip a coin by simply shaking your device. Don't have enough room to shake it? Tap on the large easy to read coin instead. Our random flipping engine gives you a perfectly equal chance of either heads or tails, and the large read out will allow you to easily see the results. Now you can settle any bet with anyone.