The central banks are flooding the markets w/ currency right now to try and bail out the banks who took on bad debt.
The European central bank floated more currency(~100bn) than the Fed did(~60bn), so I think that is why the dollar gained a little on the Euro over the past few days.
http://finance.yahoo.com/q/bc?s=EURUSD=X&t=3m&l=on...