These are some websites that I find very useful. The first site gives you sunrise and sunset data, which is essential information. Navigating at night adds a whole new array of difficulty. The second site allows you to find out the current magnetic declination for a location.
US Navel Oceanography Portal Complete Sun and Moon Data (worldwide by latitude and longitude)
National Geophysical Data Center Magnetic Declination Calculator
Tags: magnetic declination, navigation, sunrise, sunset