My app runs well on my quad-core machine. It is 'embarrasingly parallel', with about 100K processes, and thus nicely suited to run on a cluster of machines. However, I have trouble finding documentation on how to spread all those processes out on all available nodes in the cluster.
The documentation for distributed Erlang seems to focus on server-client apps, where each node is a client running a single app, and you specify manually which node runs which process.
You can certainly distribute an Erlang program across multiple cores and computers in a cluster. It was designed for that sort of thing.