Currently, best results are achieved with the Mucke model checker (version 0.3.5 is known to work). Theory MuCalculus provides the syntactic and oracle interfaces, while MuckeExample1 and MuckeExample2 demonstrate the model checker tactic mc_mucke_tac in action. To run the examples yourself, you only have to point MUCKE_HOME in Isabelle's etc/settings to the place where the Mucke binary has been installed.
In order to support more realistic applications, the HOLCF/IOA/Modelcheck session augments this basic mechanism by further infrastructure for proofs about I/O automata. There is a separate paper available, describing model checking in Isabelle/IOA in more detail.