Really fast to do. It's all done with distance lights. Start with one and make it sky blue, turn shadows off, set intensity around 5 and aim it at about a 45 degree angle down. Then duplicate it and rotate 30 degrees. Continue duplicating until you have 12 lights. (sometimes 6 lights rotated at 60 degrees is adequate) 

You can then create a new distant light for the sun and position it where you want or link it to a Realistic Sky. 

If you have shiny objects in your scene, this isn't the best thing to do because there will be multiple highlights on your object. However, for non reflective objects and outdoor scenes it works great.