The download button opens the iTunes App Store, where you
may continue the download process. You must have iTunes installed with an
active iTunes account in order to download and install the software. This
download may not be available in some countries.
From tenea tecnologias:
Do you know teneaPhone? The definitive social phone. Free calls to your address book contacts and your buddies on Facebook, Twitter, LinkedIn and other social networks. With teneaPhone is possible. You can create groups with buddies and make a conference with them. You would get the chance to chat with all your friends, individually or in groups, sharing any file you wish.Even if the app is not running or you have it in background mode, you will receive notifications of incoming calls!!! Also you can send messages to your contacts at any time, even notifying them that they've missed calls.