This may have been done before but i can't find it on here
RAWR!
Default your Colours (D)
Open your new Document at about 400 x 400
Filter>Render>Clouds
Filter>Render>Lighting Effects
Change the Lighting Effect Colours to Pure Orange And Pure Red
Omni
Play around with your settings until you get a flamy feel
Your done!
It should look something like this:
http://img.photobucket.com/albums/v1...eTutresult.jpg
Post up your Results!