We develop systematic string techniques to study brane world effective
actions for models with magnetized (or equivalently intersecting) D-branes. In
particular, we derive the dependence on all NS-NS moduli of the kinetic terms
of the chiral matter in a generic non-supersymmetric brane configurations with
non-commuting open string fluxes. Near a N=1 supersymmetric point the effective
action is consistent with a Fayet-Iliopoulos supersymmetry breaking and the
normalization of the scalar kinetic terms is nothing else than the Kahler
metric. We also discuss, from a stringy perspective, D and F term breaking
mechanisms, and how, in this generic set up, the Kahler metric enters in the
physical Yukawa couplings.Comment: 52 pages, 3 figures; several references adde