I am planning to go from puerto varas to bariloche on 5.3.2013. Looking for regular bus connection.
Two companies they do: Tas Choapa and Cruz del Sur every day.
Try [original link] they travel daily from Puerto Montt to Bariloche, leaving in the morning I think. There are other ways to get through though but a bit more expensive. When I was there, there were other buses leaving the bus station as well but if you are there you can visit the bus station and buy the ticket a few days beforehand and youll be fine!