  Broken symmetry ground states with uniform electron density are common in
quantum Hall systems when two Landau levels simultaneously approach the
chemical potential at integer filling factor $\nu$. The close analogy between
these two-dimensional electron system states and conventional itinerant
electron ferromagnets can be emphasized by using a pseudospin label to
distinguish the two Landau levels. As in conventional ferromagnets, the
evolution of the system's state as external field parameters are varied is
expected to be sensitive to the dependence of ground state energy on pseudospin
orientation. We discuss the predictions of Hartree-Fock theory for the
dependence of the sign and magnitude of the pseudospin anisotropy energy on the
nature of the crossing Landau levels. We build up a classification scheme for
quantum Hall ferromagnets that applies for single layer and bilayer systems
with two aligned Landau levels distinguished by any combination of real-spin,
orbit-radius, or growth direction degree-of-freedom quantum numbers. The
possibility of in-situ tuning between easy-axis and easy-plane quantum Hall
ferromagnets is discussed for biased bilayer systems with total filling factors
$\nu=3$ or $\nu=4$. Detailed predictions are made for the bias dependence of
pseudospin reversal properties in $\nu=3$ bilayer systems.
