  A simple two dimensional model of a phase growing on a substrate is
introduced. The model is characterized by an adsorption rate q, and a
desorption rate p. It exhibits a wetting transition which may be viewed as an
unbinding transition of an interface from a wall. For p=1, the model may be
mapped onto an exactly soluble equilibrium model exhibiting complete wetting
with critical exponents gamma = 1/3 for the diverging interface width and x_0 =
1 for the zero-level occupation. For 0 < p != 1 a crossover to different
exponents is observed which is related to a KPZ type nonlinearity.
