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 Dan Cohen:
This app makes it quick and easy to add and manage items for your digital Grocery Shopping List. Once you add everything to your list at home, go to the store and check off items in the List View section of the app as you take things off the shelf. When everything on your list is checked off, you know you picked up everything you needed.You can also save Shopping Lists and recall them later from a new Stored Lists tab! Store as many Shopping Lists as you want for different recipes or regular shopping sprees where you get the same stuff each time, like Sunday Brunch...Yum! No U-Turning back to the store when you are half-way home because you forgot the Milk!