  We observed with the camera FORS1 on the VLT (UT1, ANTU) 50 randomly selected
fields and analyzed the cosmic shear inside circular apertures with diameter
ranging from 0.5 to 5.0 arc-minutes. The images were obtained in optimal
conditions by using the Service Observing proposed by ESO on the VLT, which
enabled us to get a well-defined and homogeneous set of data. The 50 fields
cover a 0.65 square-degrees area spread over more than 1000 square-degrees
which provides a sample ideal for minimizing the cosmic variance. Using the
same techniques as in Van Waerbeke et al. 2000, we measured the cosmic shear
signal and investigated the systematics of the VLT sample. We find a
significant excess of correlations between galaxy ellipticities on those
angular scales. The amplitude and the shape of the correlation as function of
angular scale are remarkably similar to those reported so far. Using our
combined VLT and CFHT data and adding the results published by other teams we
put the first joint constraints on Omega_0 and sigma_8 using cosmic shear
surveys. From a deduced average of the redshift of the sources the combined
data are consistent with sigma_8\simeq (0.59 \pm 0.03) Omega_0^{-0.47} (for a
CDM power spectrum and $\Gamma=0.21$), in excellent agreement with the
cosmological constraints obtained from the local cluster abundance.
