This code sample is named TrayApp. It demonstrates how to place an icon on the tray on the today page, then how to have it activate a popup dialog.
Navigate to the solution file (*.sln), and double-click it. By default, the solution file is copied to the following folder:
C:\Program Files\Windows Mobile 6.5.3 DTK\Samples\PocketPC\CPP\win32\Trayapp
Microsoft Visual Studio launches and loads the solution.
Build the solution (Ctrl+Shift+B).
Deploy the solution (F5).