What Macbook? What Video ports does it have? you're not giving us much to work with here.
In any case, I don't think Apple ever supported more than a single external display on any Macbook or MacBook Pro. You certainly won't find an Apple-branded adapter for it.
You might want to check this out, Matrox DualHead2Go DP (Displayport edition), if you have a newer MB/MBP with a mini-displayport.
»www.matrox.com/graphics/ ··· gxm/mac/--
GO LEAFS GO!