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 Great Innovus Solutions:
CamJam is a simple to use camera application that provides improved features over the iPhone camera like timer and photo editing functionality: brightness, contrast, hue, saturation, lightness control of the captured photo. It is designed for simplicity and yet provides all complex features packed.CamJams timer is very simple to use; the slider control at bottom offers simple selection of a timer setting, just touch and scroll to set a desired time in seconds.CamJams post capture photo editing image controls are very simple to use; the rotor control at bottom offers simple selection of a desired setting (brightness, contrast, hue, saturation and lighting)CamJam is an essential companion for your iPhone camera.