How do I make a fire or explosion effect in photoshop?

Hi I was wondering how I make an explosion or firey looking effect in my pictures in photoshop. I have photoshop 6, but I will be getting 7 tomorrow most likely. Can you explain it in both? Thank you!

http://www.photoshoptechniques.com/main/defaulth.html

Try out the search up in the upper right corner because sometimes you can find what you are looking for real fast =) (not trying to be sarvastic, the fire tutorial has been asked a bunch)

This is a good one though....