  We study the effects of non-commutative QED (NCQED) in fermion pair
production, gamma + gamma -> f + bar{f} and Compton scattering, e + gamma -> e
+ gamma. Non-commutative geometries appear naturally in the context of
string/M-theory and gives rise to 3- and 4-point photon vertices and to
momentum dependent phase factors in QED vertices which will have observable
effects in high energy collisions. We consider e+ e- colliders with energies
appropriate to the TeV Linear Collider proposals and the multi-TeV CLIC project
operating in gamma gamma and e gamma modes. Non-commutative scales roughly
equal to the center of mass energy of the e+ e- collider can be probed, with
the exact value depending on the model parameters and experimental factors.
However, we found that the Compton process is sensitive to Lambda_{NC} values
roughly twice as large as those accessible to the pair production process.
