It seems more and more real estate professionals are finding out what photographers have known for some time: Homes look better in the evening.
The sky turns all sorts of great colors for great exterior images (probably the one time of day when a little extra pollution is actually helpful!), and the outside light levels more closely match the light levels inside the home for easy, dramatic interior shots. I love taking pictures of real estate in the evening.
When is the best time to shoot? I have found that if you hang around for the hour after sunset (known as "civil twilight") you are bound to get some great images. Be patient and just keep snapping away. You'll eventually find that "sweet spot" that is the last 15 minutes before the sky turns really dark. If your camera is set for the color cast of the tungsten lights inside a home, it makes the sky a beautiful, unreal shade of blue! This is especially useful if it's a cloudy evening: the cloud cover will look blue or purple instead of gray.
* I have the US Naval Observatory's Sun and Moon Data page bookmarked so I can easily look up sunset and sunrise times.