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 Jean-Guy Bergeron:
How Many Days? can be used to know the number of days passed, between two (2) dates, passed or future.***** Presently one of the best applications on App Store to proceed with this operation.How Many Days? is easy to use and elegant !In addition to giving you the number of past days (or which will run out) between this dates, you will also obtain the number of years and months.How Many Days? will also give you the associated day of the week of the two (2) selected dates !Would you like to know what day of the week you were born on ? Its easy, just select your birth date and How Many Days? will tell you which day of the week you came into this world.