Zmanin is a calculator of relevant Jewish Prayer times. Uses either the current location or a city slected from a list. When the "current location" is specified, it uses the latitude and longitude of where the phone is to calculate the times (it shows the nearset major city merely as a reference).
When selecting a city (other than current location) you can also select whether to display the time using daylight savings.
Times can be displayed according to the GR"A or Magen Avraham.
Time display calculations are configurable
Also displays the Daf Yomi, Mishna Yomit and Halacha Yomit for the current day.