Spin-wave resonance has been observed at 9 GHz in thin films of Ni-Co alloys containing between 0 and 40% CO at temperatures between 4.2 K and room temperature.The dispersion relationship, critical angle, linewidth and annealing results suggest that the surface spins are pinned by a surface layer about l00A thick. The exchange stiffness constant D is found to have a value about a quarter of that obtained by other methods, namely approximately 100 meV A2.