  We investigate the sensitivity of the Gamma-ray Large Area Space Telescope
(GLAST) to indirectly detect weakly interacting massive particles (WIMPs)
through the $\gamma$-ray signal that their pair annihilation produces. WIMPs
are among the favorite candidates to explain the compelling evidence that about
80% of the mass in the Universe is non-baryonic dark matter (DM). They are
serendipitously motivated by various extensions of the standard model of
particle physics such as Supersymmetry and Universal Extra Dimensions (UED).
With its unprecedented sensitivity and its very large energy range (20 MeV to
more than 300 GeV) the main instrument on board the GLAST satellite, the Large
Area Telescope (LAT), will open a new window of discovery. As our estimates
show, the LAT will be able to detect an indirect DM signature for a large class
of WIMP models given a cuspy profile for the DM distribution. Using the current
state of the art Monte Carlo and event reconstruction software developed within
the LAT collaboration, we present preliminary sensitivity studies for several
possible sources inside and outside the Galaxy. We also discuss the potential
of the LAT to detect UED via the electron/positron channel. Diffuse background
modeling and other background issues that will be important in setting limits
or seeing a signal are presented.
