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 Standard IM:
Hello for iPhone seamlessly integrates with your phone's address book to discover your existing friends who are using Hello! No phone number, no worries. Every Hello! user is issued a unique 7-digit PIN, so you won't miss a message. Beyond messaging, Hello! includes many other cool features, such as group chat, photo exchange, Facebook status updates, push notifications and much more. Hello! works internationally too, so you can connect anywhere, any time.
