  In this paper we prove propagation estimates for two-cluster scattering
channels of N-body Schr\"odinger operators. These estimates are based on the
estimate similar to Mourre's commutator estimate and the method of Skibsted. We
also obtain propagation estimates with better indices using projections onto
almost invariant subspaces close to two-cluster scattering channels. As an
application of these estimates we obtain the resolvent estimate for two-cluster
scattering channels and microlocal propagation estimates in three-body problems
without projections. Our method clearly illustrates evolution of the solutions
of the Schr\"odinger equation.
