Brushes are a fun way to add some spice to your Photoshop tool box. And almost any image can be turned into a brush! Here are a couple of tutorials I found that will help you understand the many uses of brushes in Photoshop.

Fire Brushes! - (horse artwork from Diviant art)

More fun with brushes!

Have fun with those brushes! (Here is a link to some more fun brushes to down load!)