Back in September, Wynn Resorts CEO Steve Wynn was spending two hours each day on Chinese lessons. At age 65, Wynn is worth $3.4 billion -- yet he's still learning new tricks.

Why? Because the Wynn Macau -- Mr. Wynn's latest megacasino -- was getting set to open just off the coast of China. That's right on the doorstep of some 3 billion potential customers.

Big bets for big paydays
How has the Wynn Macau fared? Analysts see it tracking above previous estimates, and contributing some $300 million in EBITDA in 2007.

But Steve Wynn isn't the only billionaire going gaga over foreign markets. Wynn rival and Las Vegas Sands CEO Sheldon Adelson, himself worth $26.5 billion, is making a similar investment in Macau's potential. Then there's the large number of companies, from Texas Instruments (NYSE:TXN) to Whirlpool (NYSE:WHR) to Caterpillar (NYSE:CAT), whose recent earnings reports were boosted by strong overseas growth. As economist Joseph Carson told The Wall Street Journal yesterday, "The international influence on firms' profits has never been so strong."

Entrepreneurs and investors alike
Meanwhile, there are the master investors who have been buying up foreign stocks at a rapid clip. NWQ Managers has large stakes in Papua New Guinea's Lihir Gold (NASDAQ:LIHR) and Taiwan's Chunghwa Telecom (NYSE:CHT); Chris Davis also has a sizeable stake in Chunghwa; and Charles Brandes has been investing recently in both Chunghwa, Brilliance China Automotive Holdings (NYSE:CBA), and a number of other Asian businesses.

Even Warren Buffett stoked the international frenzy earlier in '06, with purchases of PetroChina and Israel's Iscar Metalworking.

The question we need to ask
So -- and you had to know I was coming around to this -- what have you been adding to your portfolio lately?

Me? I know I'm underexposed to international stocks, and I've resolved to make 2007 the year I do something about that. One place I'm set to start is at our new Global Gains international investing service. You can join me free for 30 days by clicking right here.

This article was originally published on Jan. 19, 2007. It has been updated.

Tim Hanson owns shares of Wynn Resorts. Chunghwa Telecom is an Income Investor selection. No Fool is too cool for disclosure.