I'm a big fan of the Photographer's Ephemeris. I've come across some youTube videos for it which should hopefully give you some ideas of why I think this program is of value. You can get this program from Stephen's web site or if you have an iPhone or iPad, then I strongly urge you to get the app he's written for it. It works very nicely on the iPad and I hope to give you all some more insight to my use of it on my travels in the future.
As photographers, there's little point in just going some place and hoping for good light. It can often be that the light is in the wrong place and you've spent a whole day getting some place.
I'm going to Ethiopia later this year to shoot around the rock hewn churches of Lalibela, so I aim to give Stephen's app a bit of a work out on this trip and perhaps a few others around Scotland.