  Black hole solutions in the context of a generic matter-coupled
two-dimensional dilaton gravity theory are discussed both at the classical and
semiclassical level. Starting from general assumptions, a criterion for the
existence of black holes is given. The relationship between conformal anomaly
and Hawking radiation is extended to a broad class of two-dimensional dilaton
gravity models. A general and simple formula relating the magnitude of the
Hawking effect to the dilaton potential evaluated on the horizon is derived.
