  We extend our calculations with the second-order tree-level and tadpole
improved next-nearest-neighbor action to meson-meson systems. Correlation
matrices built from interpolating fields representing two pseudoscalar mesons
(pion-pion) with relative momenta p are diagonalized, and the mass spectrum is
extracted. Link variable fuzzing and operator smearing at both sinks and
sources is employed. Calculations are presented for two values of the hopping
parameter. The spectrum is used to discuss the residual interaction in the
meson-meson system.
