Just found a nifty little app on the app store (Sunrise). Based on your current location, it tells you the time of sunrise and sunset. Default is for the current day, but you can change it to dates in the future. Unfortunately it only works for your current location (no option to select other locations).
For $0.99 it should be quite convenient when planning early morning/late evening shooting.
For $0.99 it should be quite convenient when planning early morning/late evening shooting.