  There is mounting evidence that a self-consistent model for particle cold
dark matter has to take into consideration spatial inhomogeneities on
sub-galactic scales seen, for instance, in high-resolution N-body simulations
of structure formation. Also in more idealized, analytic models, there appear
density enhancements in certain regions of the halo. We use the results from a
recent N-body simulation of the Milky Way halo and investigate the gamma-ray
flux which would be produced when a specific dark matter candidate, the
neutralino, annihilates in regions of enhanced density. The clumpiness found on
all scales in the simulation results in very strong gamma-ray signals which
seem to already rule out some regions of the supersymmetric parameter space,
and would be further probed by upcoming experiments, such as the GLAST
gamma-ray satellite. As an orthogonal model of structure formation, we also
consider Sikivie's simple infall model of dark matter which predicts that there
should exist continuous regions of enhanced density, caustic rings, in the dark
matter halo of the Milky Way. We find, however, that the gamma-ray signal from
caustic rings is generally too small to be detectable.
