yeah, real time. I'm using UDK, personally. I've tried Fume FX, it's real nice but I can't see how to use it's stuff in real time applications. Flipbooks/sampled loops of fire I tried aren't great, (too noticeable) on animated planes.
Ideally I'm open to any suggestions, tips, anything anyone has found useful for particle based real-time fx. or anything fire related in a game situation.