  We study the sectional curvature of plane distributions on 3-manifolds. We
show that if the distribution is a contact structure it is easy to manipulate
this curvature. As a corollary we obtain that for every transversally oriented
contact structure on a closed 3-dimensional manifold $M$ there is a metric,
such that the sectional curvature of the contact distribution is equal to -1.
We also introduce the notion of Gaussian curvature of the plane distribution.
For this notion of curvature we get the similar results.
