Almost endless threads on Pavonis here http://www.home-barista.com/levers/ here http://www.coffeegeek.com/forums/espresso/leverespresso and a few outcasts in CS as well. The Australian distributors Euro Espresso are very helpful also. mod edit- commercial site link removed to comply with site sales and posting policy
Pavonis are not the easiest espresso machines to use but well worth the experience. Just be prepared to lose *a bit of sanity along the way.