Currency Shares.com - 9 Non leveraged currency shares operated by Rydex Investments.
Invesco Power Shares - Broad range of leveraged etfs including regular us dollar up/down units.
IPath ETN - Broad range of etns including currency notes on the euro, british pound, and japanese yen.
Proshares - A large selection of ets including 2x Euro and Yen currency up/down units.
Macro Markets - Housing Market Index trust 3x leverage on 10 u.s. cities with currency units in the works.
Market Vectors ETN - Double Long + Double Short Euro, also regular Chinese Renminbi and Indian Rupee.