  We investigate non perturbatively scattering properties of Goldstone Bosons
in an SU(2) gauge theory with two Wilson fermions in the fundamental
representation. Such a theory can be used to build extensions of the Standard
Model that unifies Technicolor and pseudo Goldstone composite Higgs models. The
leading order contribution to the scattering amplitude of Goldstone bosons at
low energy is given by the scattering lengths. In the context of technicolor
extensions of the Standard Model the scattering lengths are constrained by WW
scattering measurements. We first describe our setup and in particular the
expected chiral symmetry breaking pattern. We then discuss how to compute them
on the lattice and give preliminary results using finite size methods.
