Here's an interesting article from the Wall Street Journal about Warren Buffet and the difficulty with taking up forex positions based on fundamental economic analysis alone:
From the Wall Street Journal "In the early 1920s, John Maynard Keynes attempted to apply his economic views to speculation in the foreign-exchange markets. Though Mr. Keynes was nearly bankrupted by this experience, he learned a valuable lesson: It is difficult to earn money in forex markets from taking positions based on fundamental economic analysis. Recent losses from shorting the dollar suggest Warren Buffett is receiving a similar lesson.