I don't think that this has been posted before:
http://www.positech.co.uk/content/explo ... rator.html
A nice little program to generate explosion sprites.
Downsides:
The mouse cursor disappears on my system while the program is active (alt-tabbing finds it again).
I can't figure out a way to make the explosion graphics bigger/smaller.
Other than that, however, it produces some nice, unique-to-your-project explosion spites.