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 AppInTheSky.com:
Find Tweets from people around you! Or from any other specified location! Wow! Yes, see in the map the Tweets location. Designed exclusively for iPad, iPhone and iPod Touch Download today!
