this is my creation wich i've made with Particular 2, it was hard to create a realistic feel of smoke but I hope you like it.
If there are questions feel free to ask them, I will help you as good as possible.
Used programs and plu-ins:
After Effects CS5 ------> Trapcode Particular 2
Try to only use the AUX tab in particular 2, set the opacity of the main particles to 0%, and play with the settings in the AUX tab, and don't forget to set the X-Wind to a negative value.