  10 to 10^5 solar mass black holes with dark matter spikes that formed in
early minihalos and still exist in our Milky Way Galaxy today are examined in
light of recent data from the Fermi Gamma-Ray Space Telescope (FGST). The dark
matter spikes surrounding black holes in our Galaxy are sites of significant
dark matter annihilation. We examine the signatures of annihilations into
gamma-rays, electrons and positrons, and neutrinos. We find that some
significant fraction of the point sources detected by FGST might be due to dark
matter annihilation near black holes in our Galaxy. We obtain limits on the
properties of dark matter annihilations in the spikes using the information in
the FGST First Source Catalog as well as the diffuse gamma-ray flux measured by
FGST. We determine the maximum fraction of high redshift minihalos that could
have hosted the formation of the first generation of stars and, subsequently,
their black hole remnants. The strength of the limits depends on the choice of
annihilation channel and black hole mass; limits are strongest for the heaviest
black holes and annhilation to $b \bar{b}$ and $W^+W^-$ final states. The
larger black holes considered in this paper may arise as the remnants of Dark
Stars after the dark matter fuel is exhausted and thermonuclear burning runs
its course; thus FGST observations may be used to constrain the properties of
Dark Stars. Additionally, we comment on the excess positron flux found by
PAMELA and its possible interpretation in terms of dark matter annihilation
around these black hole spikes.
