  The Newman-Penrose-Perjes formalism is applied to Sasakian 3-manifolds and
the local form of the metric and contact structure is presented. The local
moduli space can be parameterised by a single function of two variables and it
is shown that, given any smooth function of two variables, there exists locally
a Sasakian structure with scalar curvature equal to this function. The case
where the scalar curvature is constant ($\eta$-Einstein Sasakian metrics) is
completely solved locally. The resulting Sasakian manifolds include $S^3$,
$Nil$ and $\tilde{SL_2R}$, as well as the Berger spheres. It is also shown that
a conformally flat Sasakian 3-manifold is Einstein of positive scalar
curvature.
