Classical communication through quantum channels may be enhanced by sharing
entanglement. Superdense coding allows the encoding, and transmission, of
up to two classical bits of information in a single qubit. In this paper, t
he maximum classical channel capacity for states that are not maximally ent
angled is derived. Particular schemes are then shown to attain this capacit
y, first for pairs of qubits, and second for pairs of qutrits.