You can find here OCaml bindings for a set of C libraries. These bindings requires the OCaml compiler, the CamlIDL stub code generator, and of course the interfaced C library,
It requires CUDDAUX, a small extension of the CUDD BDD library
You can alternatively download the bundle named cuddaux+mlcuddidl using subversion.You can browe directly the subversion repository. You can find more information about downloading from subversion repository.