I think America and Europe are busy stockpiling petrol and ramping up alternatives in preparation.
I hope so. I think the Europeans may be in denial, unfortunately, but there must be some sensible folk among them who see what's on the horizon.
I don't know when it's likely to happen. Bush doesn't have much longer in office, relatively speaking, and in any case, there is not much time before Iran has nuclear capacity (which it may already have, IMO, but not necessarily all of the technical support to employ it or perhaps to readily produce more). I guess we should all be stockpiling essentials, because it will probably be sooner rather than later.