  We present a global measurement of the integrated Sachs-Wolfe (ISW) effect
obtained by cross-correlating all relevant large scale galaxy data sets with
the cosmic microwave background radiation map provided by the Wilkinson
Microwave Anisotropy Probe. With these measurements, the overall ISW signal is
detected at the ~ 4.5 sigma level. We also examine the cosmological
implications of these measurements, particularly the dark energy equation of
state w, its sound speed, and the overall curvature of the Universe. The flat
LCDM model is a good fit to the data and, assuming this model, we find that the
ISW data constrain Omega_m = 0.20 +0.19 -0.11 at the 95% confidence level. When
we combine our ISW results with the latest baryon oscillation and supernovae
measurements, we find that the result is still consistent with a flat LCDM
model with w = -1 out to redshifts z > 1.
