Start Screen in WM 6.5 has changed a lot from Start Menu in the previous versions of Windows Mobile. HoneyComb design makes it possible to use your finger to launch applications. You don’t have to take out the stylus anymore atleast, just to launch an application.
Builtin applications in WM 6.5 have very high quality icons that are displayed on the Start Screen. Application developers who want to give similar user experience to their users has got to do some work. They need to create and ship a PNG icon file along with their application. Some registry changes are required to inform the OS to use specified png file as icon instead of one embedded in the executable.
Check out the following two posts that explain the steps to create the png file icons and how to use them in your application: