This IPad/Touch application is lovely! You are on a trip in a foreign city, in a foreign country and you would like to know how much time you have left until the sun goes down or you want to know when you can enjoy the sunrise at the beach?
Sun Circuit is a great little app which displays a countdown to the next sunrise or sunset exact to the second.
This app shows not only the countdown at your current location (iPhone GPS, iPod Touch Wi-Fi) but also lets you add locations from all over the world. You can add up to 15 locations including your current location.
Sun Circuit iAd supported and despite the beautiful graphics and intuitive handling you can get it for free! Search Sun Circuit in ITunes Store under Apps.