  We present a quantitative comparison between extensive Monte Carlo
simulations and self-consistent field calculations on the phase diagram and
wetting behavior of a symmetric, binary (AB) polymer blend confined into a
film. The flat walls attract one component via a short range interaction. The
critical point of the confined blend is shifted to lower temperatures and
higher concentrations of the component with the lower surface free energy. The
binodals close the the critical point are flattened compared to the bulk and
exhibit a convex curvature at intermediate temperatures -- a signature of the
wetting transition in the semi-infinite system. Investigating the spectrum of
capillary fluctuation of the interface bound to the wall, we find evidence for
a position dependence of the interfacial tension. This goes along with a
distortion of the interfacial profile from its bulk shape. Using an extended
ensemble in which the monomer-wall interaction is a stochastic variable, we
accurately measure the difference between the surface energies of the
components, and determine the location of the wetting transition via the Young
equation. The Flory-Huggins parameter at which the strong first order wetting
transition occurs is independent of chain length and grows quadratically with
the integrated wall-monomer interaction strength. We estimate the location of
the prewetting line. The prewetting manifests itself in a triple point in the
phase diagram of very thick films and causes spinodal dewetting of ultrathin
layers slightly above the wetting transition. We investigate the early stage of
dewetting via dynamic Monte Carlo simulations.
