  Cosmological weak lensing by the large scale structure of the Universe,
cosmic shear, is coming of age as a powerful probe of the parameters describing
the cosmological model and matter power spectrum. It complements CMB studies,
by breaking degeneracies and providing a cross-check. An important measure of
the cosmic shear signal are the shear correlation functions; these can be
directly calculated from data, and compared with theoretical expectations for
different cosmological models and matter power spectra. We present a Monte
Carlo method to quickly simulate mock cosmic shear surveys. One application of
this method is in the determination of the full covariance matrix for the
correlation functions; this includes redshift binning and is applicable to
arbitrary survey geometries. Terms arising from shot noise and cosmic variance
(dominant on small and large scales respectively) are accounted for naturally.
As an illustration of the use of such covariance matrices, we consider to what
degree confidence regions on parameters are tightened when redshift binning is
employed. The parameters considered are those commonly discussed in cosmic
shear analyses - the matter density parameter, dark energy density parameter
(classical cosmological constant), power spectrum normalisation and shape
parameter. We incorporate our covariance matrices into a likelihood treatment,
and also use the Fisher formalism to explore a larger region of parameter space
(abridged).
