The proliferation of WiFi means that these days you can get connected for free from lots of places around town. If you want to track exactly what is being sent to and from your Pocket PC via its WiFi connection then check out PPC InterfaceMonitor.
The app provides a very visual way of monitoring and analysing incoming and outgoing traffic on your device. There are a series of indicators that display a range of information, such as the precentage of time connected over a period of time, total traffic sent and received, and information on the internal interface. Easy access to all this data is facilitated by a tabbed user environment, allowing you to flick quickly between different types of information.
If you are a regular WiFi user and want to keep track of your traffic, PPC InterfaceMonitor provides a very clear way of doing so.