Our Economist House Caller, Simon Johnson has an interesting post: he's hearing that the 7 richest countries will announce a major intervention into world currency markets this weekend.
Coordinated intervention, announced over the weekend most likely, will involve selling dollars, selling yen, buying euros and pounds. This can calm things, by showing there are no one way bets. (Will the Chinese be involved?)
We Americans might instinctively like hearing that the dollar is getting stronger. But it can be destabilizing if the dollar is getting stronger too fast and erratically.