This video shows the latest development by Farsthary of Tinker Code (farsthary.wordpress.com) for Blender 2.5 that brings in very specific controls over vortices. Imagine using it to show snow in the wake of a car on the road.. or smoke rising around objects or the jet stream behind a jet.
It is a boundless solution, meaning it's not limited to a domain (rectangular bounding area), and uses the current Blender particle system which is a
second order simulation system (particles act as a source of force field). The current vortex particle field has a very limited rotational vector which is locked to the particle velocity direction. The simple patch this video illustrates allows more user control. Watch yourself!