  Pseudo-Goldstone boson contributions to $t\bar{t}$ production rates in
technicolor models with and without topcolor at the $\sqrt{s}=0.5 and 1.5$ TeV
photon colliders and hadron colliders are reviewed. For reasonable ranges of
the parameters, the contributions are large enough to be experimentally
observable. Models with topcolor, without topcolor and the MSSM with
$\tan\beta\geq 1$ can be experimentally distinguished.
