  Selected results on estimating cosmological parameters from simulated weak
lensing data with noise are presented. Numerical simulations of ray tracing
through N-body simulations have been used to generate shear and convergence
maps due to lensing by large-scale structure. Noise due to the intrinsic
ellipticities of a finite number of galaxies is added. In this contribution we
present our main results on estimation of the power spectrum and density
parameter Omega from weak lensing data on several degree sized fields. We also
show that there are striking morphological differences in the weak lensing maps
of clusters of galaxies formed in models with different values of Omega.
