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 Fivetime Productions:
Plankers! Ever wonder just how well you were planking? If your planks were better than the planks of your friends? Well now you can know for sure! iPlank allows you to take planking photos, or load your saved planks and put them through our secret plankometer formula to determine the accuracy and awesomeness of your plank! It's simple to use: touch the head, feet and middle of the planker, then sit back and relax as the plankometer determines firstly if your plank is a legal plank, and secondly just how good it is! You'll be presented with your plank angle. Share it on Facebook, Twitter or email, and you will be awarded a score out of 100 which your friends will see in envy. Compete with your friends to determine who's the best planker! Your plank pic, angle and score will all be posted online for everyone to view, making you the coolest planker on the planket!