In multi-valued model checking, a temporal logic formula is interpreted relative to a structure not as a truth value but as a lattice element. In this paper we present new algorithms for multi-valued model checking. We first show how to reduce multi-valued model checking with any distributive DeMorgan lattice to standard, two-valued model checking. We then present a direct, automata-theoretic algorithm for multivalued model checking with logics as expressive as the modal mu-calculus. As part of showing correctness of the algorithm, we present a new fundamental result about extended alternating automata, a generalization of standard alternating automata.