Duality and Massless Monopoles
  Duality arguments suggest the existence of massless magnetic monopoles in gauge theories with the symmetry broken to a non-Abelian subgroup. I discuss how these arise and show how they are manifested as clouds of massless fields surrounding massive monopoles. The dynamics of these clouds is discussed, and the scattering of massless monopole clouds and massive monopoles is described. 
Erick J. Weinberg