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 Rod Howarth:
Travelling in a group? Stay in the loop, with Convoy. Free ad supported version!Convoy is aimed at groups of people who are driving in separate vehicles to a particular destination. Normally when travelling in a group it is quite hard to keep up with your fellow drivers, particularly if you are all trying to follow one particular person. You often run into problems with traffic and red lights, and when you want to pull over for a pit stop, it is a pain to try and get into contact with all the different vehicles. Convoy solves this problem by giving you a map with live updates of where your friends are located. If you want to communicate with other people in your Convoy, you can indicate locations on the map where you wish to pullover for a pit stop and point out hazards. If you want to send a more detailed message there is a group text message feature that sends to everyone in the Convoy at once. To use the app, one person creates a new Convoy, and then sends the Convoy code to the others. The others then enter this code into their copy of Convoy to join the session. As long as you have Convoy open, your location will be updated with our server every 5 seconds, and the locations of your fellow travellers will be updated on your map. It is important to note that GPS, 3G internet and having the screen constantly running uses up battery life on your device. If you are travelling over a long distance, it's recommended that you plug your device into a car charger. Also note that operating your phone while driving is illegal in many places, so please get your fellow travellers to use the communication buttons or pull over first.