I'm rather certain I've blogged about this gem before:

Athan and recitation before the Athan even when the device is off. Also, This software contains Prayer table, Prayer schedule , Hijri Calendar and Hijri to Georgian conversion, Qibla according to your location and position of the sun. Furthermore, it contains lunar calendar, moon age and Islamic Holidays Added to your calendar. Finally, it support Today Screen plugging display to display the prayer time and date in Hijri and to control the Azan voice.

[ Pocket Islam Smartphone ]

For any gadget geek Muslim with a Windows Mobile device, this one is a must.