You can use a Level Translator. TI, Fairchild and ON Semi make quite a few. An example is the TI TXS0104E 4 bit bidirectional translator, which runs at up to 24 Mbps. This one is auto direction, and relies on an edge to set direction (as do the Fairchild FXLA and FXMA translators). For manual direction translators you could look at the On Semi 74LVC2T45 in which you choose the direction, and they have high current drive and high transfer rates (up to 420 Mbps). The manual direction translators are more bullet proof.
