  In String theory realizations of inflation, the end point of inflation is
often brane-anti brane annihilation. We consider the processes of reheating of
the Standard Model universe after brane inflation. We identify the channels of
inflaton energy decay, cascading from tachyon annihilation through massive
closed string loops, KK modes, and brane displacement moduli to the lighter
standard model particles. Cosmological data constrains scenarios by putting
stringent limits on the fraction of reheating energy deposited in gravitons and
nonstandard sector massive relics. We estimate the energy deposited into
various light degrees of freedom in the open and closed string sectors, the
timing of reheating, and the reheating temperature. Production of gravitons is
significantly suppressed in warped inflation. However, we predict a residual
gravitational radiation background at the level $\Omega_{GW} \sim 10^{-8}$ of
the present cosmological energy density. We also extend our analysis to
multiple throat scenarios. A viable reheating would be possible in a single
throat or in a certain subclass of multiple throat scenarios of the KKLMMT type
inflation model, but overproduction of massive KK modes poses a serious
problem. The problem is quite severe if some inner manifold comes with
approximate isometries (angular KK modes) or if there exists a throat of modest
length other than the standard model throat, possibly associated with some
hidden sector (low-lying KK modes).
