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 Citizen Observer:
The Cambridge PD Tips application, developed by CitizenObserver, provides citizens the ability to submit anonymous tips to organizations that are using the tip411 web based application for reviewing, managing and responding to tips. The application augments the anonymous SMS Text tip and web tip capability that is also offered by CitizenObserver. Key Features Include: Anonymous 2 way interaction between the tipster and the participating law enforcement agency or organization. Attach images to tips Intuitive interface makes it easy to quickly send a tip and get a responseCitizenObserver also offers text/email targeted alerting, social media publishing, and public crime mapping solutions designed to a help engage the public to create safer communities and lower costs to law enforcement.