  The most remarkable and interesting feature of brane world scenario is the
use of bulk's curvature to localize gravity on the brane, albeit with fine
tuning of the brane and bulk parameters. For FRW expanding universe on the
brane, it is a moving hypersurface in Schwarzschild anti de Sitter bulk
spacetime. We show that zero mass gravitons have bound state on the brane for
suitable values of brane and bulk parameters. There occur various cases giving
rise to different cosmological models, in particular we discuss a model with
positive cosmological constant on the brane.
