  Massive colliding wind binary stars serve as laboratories for the study of
strong-shock physics. In these systems fundamental flow parameters (velocities,
densities, directions) are often well known, and photon fields important for
Compton scattering and ionization are usually defined or constrained as well.
In this paper we review observed X-ray and radio characteristics of some
important colliding wind systems. We discuss how X-ray and radio observations
of these systems can be used to test models of the collision of massive flows
in the presence of intense UV radiation and magnetic fields.
