Jim Peterson at Schwab Investment Research advices that to invest in foreign funds you should:

1. invest a one quarter of the money you have allocated for stocks adjusting upward or downward depending on how you feel about the world economy
2. Two-thirds should be in developed economies such as Japan and Europe
3. The remainder should be divided between smaller companies in developed markets and large companies in emerging markets

Read More about foreign stock funds at Akron Beacon Journal