  We present a theory to model carrier mediated ferromagnetism in concentrated
or diluted local moment systems. The electronic subsystem of the Kondo lattice
model is described by a combined equation of motion / coherent potential
approximation method. Doing this we can calculate the free energy of the system
and its minimum according to the magnetization of the local moments. Thus also
the Curie temperature can be determined and its dependence on important model
parameters. We get qualitative agreement with the Curie temperatures'
experimental values of Ga$_{1-x}$Mn$_x$As for a proper hole density.
