Starting with Windows Mobile 2003 SE, Microsoft provided support for square screens (240 by 240 instead of the usual 240 by 320). With the imminent release of the hw6500 and likely other Windows Mobile devices using square screens, designers will need to incorporate support for different screen types in their software. MSDN has published an article called “Porting GAPI Games from Portrait to Square Screens” that looks at some alternatives.
Source: PocketPC Paradise