Uniform magnetization precession in the ferromagnetic state of La0.67Sr0.33MnO3 films grown on different substrates is investigated in the 50–300K temperature range in magnetic fields of up to 1.3T. The precession was induced by an optical pump pulse and probed by a time-delayed pulse using magneto-optical Kerr effect. The measured field dependence of the precession frequency agrees well with calculation from the Landau-Lifshitz-Gilbert equation using different uniaxial anisotropies for different substrates. The field-dependent relaxation times of the exponentially decaying precession are in 100–1400ps range. This work is supported in part by NSF (DMR-0137322, IMR-0114124, and PSU MRSEC DMR-0213623), DOE (DE-FG02-04ER46127), and the Petroleum Research Fund.