  Torsional (shear) oscillations of neutron stars may have been observed in
quasiperiodic oscillations of Magnetar Giant Flares. The frequencies of these
modes depend on the shear modulus of neutron star crust. We calculate the shear
modulus of Coulomb crystals from molecular dynamics simulations. We find that
electron screening reduces the shear modulus by about 10% compared to previous
Ogata et al. results. Our MD simulations can be extended to calculate the
effects of impurities and or polycrystalline structures on the shear modulus.
