  The probability distribution of the conductance at the mobility edge,
$p_c(g)$, in different universality classes and dimensions is investigated
numerically for a variety of random systems. It is shown that $p_c(g)$ is
universal for systems of given symmetry, dimensionality, and boundary
conditions. An analytical form of $p_c(g)$ for small values of $g$ is discussed
and agreement with numerical data is observed. For $g > 1$, $\ln p_c(g)$ is
proportional to $(g-1)$ rather than $(g-1)^2$.
