After watching the awsome "flame-thrower"-tutorial from blenderguru.com I wanted to give the particle and smoke system a try. I modelled a very simple animation of a dragon instead of a flamethrower and I haven't added any fancy materials or compositing stuff yet. But I think the fire-effect is still very impressive
you can download my blender file here - but be warned - it takes a while to render.
here is a still form the animation, in case you can't watch the video