  We propose a simple description of the spectrum of edge states in the quantum
Hall regime, in terms of semiclassical quantization of skipping orbits along
hard wall boundaries, ${\cal A}=2 \pi (n+\gamma) \ell_B^2$, where ${\cal A}$ is
the area enclosed between a skipping orbit and the wall and $\ell_B$ is the
magnetic length. Remarkably, this description provides an excellent
quantitative agreement with the exact spectrum. We discuss the value of
$\gamma$ when the skipping orbits touch one or two edges, and its variation
when the orbits graze the edges and the semiclassical quantization has to be
corrected by diffraction effects. The value of $\gamma$ evolves continuously
from $1/2$ to $3/4$. We calculate the energy dependence of the drift velocity
along the different Landau levels. We compare the structure of the
semiclassical cyclotron orbits, their position with respect to the edge, to the
wave function of the corresponding eigenstates.
