Sol: Daylight Clock
$0.99 from Alexander Valys 
Sol is a 24-hour daylight clock. For any location on the planet, Sol displays how many hours of each day are spent in sunlight, how many are spent at nighttime, and how many are spent in twilight. Whether you’re a backpacker who wants to know how long you have to get to your car before it gets dark, an astronomer who needs to know how many hours you can spend making observations before dawn, a private pilot who needs to land your plane before civil twilight, or just someone who wants to know how much daylight will be left when you get home from work, Sol does what you need.
Sol can calculate sunrise, sunset, and civil, nautical, and astronomical twilight for anywhere on Earth. And with a database of over 2.3 million locations, you’ll never need to look up your latitude and longitude.
iPhone Apps (3) - Focalware
Someone has made an iPhone app that is almost exactly what I was thinking about need; Focalware by Spiral Development. This very handy app will show you the position of the sun and the moon, their rise and set times for any date and any …
http://jonroemer.typepad.com/jon_roemer/2008/12/iphone-apps-3-focalware.html
