  We have performed 75As Nuclear Magnetic Resonance (NMR) measurements on
aligned powders of the new LaO0.9F0.1FeAs superconductor. In the normal state,
we find a strong temperature dependence of the spin shift and Korringa behavior
of the spin lattice relaxation rate. In the superconducting state, we find
evidence for line nodes in the superconducting gap and spin-singlet pairing.
Our measurements reveal a strong anisotropy of the spin lattice relaxation
rate, which suggest that superconducting vortices contribute to the relaxation
rate when the field is parallel to the c-axis but not for the perpendicular
direction.
