Tracking Viewer for Flex is a ready-to-use web-mapping application that comes with Tracking Server and is also available as a free download. The latest version is based on the ArcGIS Viewer for Flex, and uses a Tracking Widget to connect to Tracking Server and subcribe to real-time tracking services.
The source code of Tracking Viewer for Flex can also be downloaded from the Tracking Server Resources group in the ArcGIS Online gallery, allowing for customization.
A stand-alone Tracking Viewer (also built using Flex technology) was released with Tracking Server 10.0. The primary difference between this version and the most current version is that this version is not widget-based. It is a stand-alone Web application.
If you are using this version of Tracking Viewer, you can visit the online help documentation to learn more.
You can also check the Tracking Server Resources group in the ArcGIS Online gallery to download other cool tracking widgets!