Both seek to explain the world. Science primarily through observation and testing and religion primarily through thinking and story telling. After thinking on it a bit, there is one simple way to distinguish the two: prediction.
XKCD T-shirt
One of the best examples in my mind of science making accurate predictions is the periodic table. Prior to the periodic table, chemists had trouble organizing the atomic elements, but when they figured out a good way to organize it, not only did it describe known elements in a logical order, but was also able to predict the existence of elements not yet discovered (which were later discovered). Religion can’t predict these kind of physical world things. However, I must admit that it can make some “predictions”. For example, following the 10 commandments would make society a better place, a pretty good and accurate prediction IMO.
Of course, if the world ends in 2012 I’m completely wrong.
Astrology takes a large role in many religions and is almost entirely based on prediction. This is where its power comes from; if you can predict the lunar eclipses (and no one else can) you can tell the people whatever you want about it.
I propose the following example:
“The gods are angry!”
“Yay! What I did worked and I have the power to convince the gods to do stuff! Give me power/money/virgins/whatever”
I would say they are interpreting/adding, separate from their prediction, something that can be seen through over time. For example, “I can cure the common cold, drink this and you’ll be fine in a week or two.”, well, if you’ve been sick before you’ll know that you’ll get over it in a week or two anyway.