Hi andylincoln,
Adequate evidence exists to say that taping, strapping or bracing is effective for ankle instability.
The latest evidence by Refshauge et al 2008, concluded that a standard taping technique (heel locks, figure of 6 and stirrups) reduces the incidence of resprain. However, the physiology is not clear.
The same paper also describes possible mechanisms of taping. Please have a look.