After Effects filter developer Philipp Spöth of Frischluft.com posted a note on the AE-List about "a friend who is working on a Smoke and Fire plugin. This will not be the usual fake stuff. So maybe you are intersted in giving him some good feedback to help him turn this into a great plugin."
Apparently the filter is Windows-only and requires NVIDIA CUDA-enabled graphics for now, which will exclude some good feedback. The developer, Jaswet.com, has set up a small forum and two example renders: IncenseTest.wmv and IncenseTest2.wmv.
Update: On the AE-List, Ko Maruyama mentioned that DigitalAnarchy was re-developing similar fluid-dynamics tools from SpeedSix (shown at NAB).