  The Laser Interferometer Gravitational Wave Observatory (LIGO) has performed
a third science run with much improved sensitivities of all three
interferometers. We present an analysis of approximately 200 hours of data
acquired during this run, used to search for a stochastic background of
gravitational radiation. We place upper bounds on the energy density stored as
gravitational radiation for three different spectral power laws. For the flat
spectrum, our limit of Omega_0<8.4e-4 in the 69-156 Hz band is ~10^5 times
lower than the previous result in this frequency range.
