I once had a dream that my grandfather had died, and sadly I awoke the next morning with the news that he had. However that is to say not all dreams are prophetic, if you're worried about someone lace a white light around them in your mind.
Well, I once had a dream that there would be a new ice cream parlour in my town and after a while (I forget how long after) there was. It was actually a little creepy because there was a guy who worked there who looked just like a guy who worked there in my dream. It actually happened, no joke.