This excerpt taken from the PBR 6-K filed Mar 31, 2009.
4.1 Functional currency
The functional currency of Petrobras, as well as all its Brazilian subsidiaries, is the Real (R$). The functional currency of some subsidiaries and special purpose entities that operate in the international economic environment is the US Dollar, and the functional currency of Petrobras Energía Participaciones S.A. (PEPSA) is the Argentine Peso.
In 2008 the Company translated the assets and liabilities of subsidiaries and specific purpose entities with a functional currency different from the Real (R$) into Reais, at the selling exchange rate prevailing at December 31, 2008, and the statements of income and cash flows at the prevailing average rates during the year. The net gain from translation in the amount of R$ 636.264 in Consolidated (R$ 452.704 in the Parent company),resulting from this process, was presented as accumulated translation adjustments in shareholders equity.