Most photographers know that the best light for photographing landscapes is usually found at sunrise and sunset. Taking photographs in the middle of the day is rarely a good idea, unless there’s a way of mitigating the glare of the midday sun, or it’s intended to be an integral part of the photograph. It’s easy, of course, to find out sunrise and sunset times online (all decent weather sites offer that information for most common locations). But I’ve also just found a great little application for identifying these times that is available (free!) for the iPod touch/iPhone. I don’t know how to post a link to it, but a search for “Daylight” in the “Apps” section of iTunes should work. Not only does it show sunrise and sunset times, but also dawn and dusk. This makes it even easier to plan ahead and catch the magical light that can transform the landscape at those times.
If you live near the sea, you might also want to know about tides. I can recommend a free App called “Marine Day Tides”.
December: I’ve also added ‘MoonPhase’… which does exactly what it says: tells you when the moon is doing what!