This application might be interesting for muslims: Get prayer (salat/salah/namaz) timings for your local city along with Qibla direction, distance and athan (azaan/azan) now on iPhone and iPod Touch!

Changes:

Athan Selection fixed for Medina
Hijri date correction fixed
iAthan now launches at prayer times automatically (however for now it still does not support waking the phone up from sleep)
City deletion problem fixed for the default city, ‘London’
Vibration alerts added

http://www.guidedways.com/mobile/iathan/download_iathan.php