Dartmouth University economist Andrew Samwick has a good post on the dollar on his blog.

In almost all cases, the sky is not falling. Prices adjust so that it hangs lower and grayer.

Expect the dollar to decline until the U.S. current account imbalances shrink substantially. Expect some of this decline to happen as major exporting countries become less willing to organize themselves around holding dollars in exchange for their goods. Expect these countries to diversify their new investments and some of their existing ones, but not to dump their dollar holdings. No other country's short-term economic interests are served by devaluing its own asset holdings, and no exporting country's long-term economic interests are served by inviting a nationalistic, political response from the U.S.

I think this is the right approach to take on the dollar's current turmoil.