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 AquaMinds Software Corporation:
NoteShare Mobile Viewer is a companion app to AquaMinds NoteShare and NoteShare Server for OS X. It can browse and display notebooks being actively shared from your Mac, or any Mac running NoteShare anywhere in the world. Changes saved by NoteShare or NoteTaker users to a shared notebook are displayed within seconds in the mobile viewer. Notebooks are automatically cached when viewed, for efficiency and for viewing offline. No tedious manual file transfers or synching is needed.NoteShare Mobile Viewer displays an accurate HTML representation of the original notebook's content and appearance. This is the same representation used by NoteShare's Web Notebooks feature. You can navigate by touching page titles and numbers, section tabs, links, and the next and previous page buttons, as well as by using touch gestures.NoteShare services sharing on your local network are automatically discovered. Other NoteShare services may be added by typing in the NoteShare service's address. Full 128-bit AES encryption is used to transmit the content of password-protected notebooks, just like the full version of NoteShare for OS X.System Requirements iPhone, iPad, or iPod Touch running iOS v4.2 or later AquaMinds NoteShare or NoteShare Server v2.5.7 or later An active network connection between the iOS device and the computer running NoteShare (for downloading and synchronizing notebooks).About AquaMinds NoteShare for OS X: Sharing Made SimpleNoteShare is a powerful desktop application for creating, publishing and sharing media rich, multi-page notebooks. Users can instantly share their notebooks with other NoteShare users for presenting, viewing and editing information. NoteShare can be used in the same room, same building and globally for connecting anytime, anywhere.
Fixed problems connecting to NoteShare via carrier data network. Fixed problems when navigating between notebooks using the title bar Back and Forward buttons. Fixed inability to find NoteShare services running on OS X 10.5 via Bonjour. Fixed some issues related to caching and offline access. Improved responsiveness when navigating a notebook while a background synch is in progress.