  We present recent Green's function Monte Carlo calculations of magnetic
moments and M1 transitions in $A \leq 9$ nuclei, which include corrections
arising from two-body meson-exchange electromagnetic currents. Two-body effects
provide significant corrections to the calculated observables, bringing them in
excellent agreement with the experimental data. In particular, we find that
two-body corrections are especially large in the A=9, $T=3/2$ systems, in which
they account for up to $\sim 20%$ ($\sim 40 %$) of the total predicted value
for the $^9$Li ($^9$C) magnetic moment.
