Small firms account for an increasing share of U.S. exports

"It is easier to sell overseas now," Trammel said. "Air travel and communication is so great that you can communicate anywhere in the world."

Lower tariffs as a result of free-trade agreements have also helped. Since the North American Free Trade Agreement with Canada and Mexico in 1993, the U.S. has entered into accords with Chile and Central America. Treaties with Peru, Colombia, Panama and South Korea are currently awaiting congressional approval.

"The free-trade agreements are really an important element for the smaller companies because tariffs and non-tariff barriers pose less difficulties for large multinationals," the U.S. Chamber's Murphy said. "For smaller enterprises, the tariffs can be a deal-breaker."

A drop in the value of the dollar, by making U.S.-made goods less expensive to foreign buyers, is also helping boost foreign demand. The dollar has fallen 11 percent against a basket of currencies from major trading partners since January 2006, according to Federal Reserve data.

A European customer eyeing an American product priced at $100, would now need to come up with only about 68 euros to make the purchase, compared with 99 euros five years ago.

Conversely, a drop in the dollar also raises the cost of producing goods overseas, encouraging American companies to do more manufacturing at home and foreign companies to set up U.S. factories, AllianceBernstein's Carson said.

"Companies are relooking at the U.S. as a production base," said Carson. "With the most productive work force in the world and with great transportation systems, you could easily see a shift in production rates" toward the U.S.

That may be one reason spending by factories on new equipment rose for a fourth straight year in 2006, according to the Commerce Department's Annual Survey of Manufacturers. The last time that occurred was from 1994 to 1998.

The increase in exports "is a very positive sign for future growth," Robert Stein, a senior economist at First Trust Advisors LP in Vienna, Va. "Now that smaller firms have a more diversified base of customers, it makes them more stable. They can plan for the future, they can invest. We can keep operations in the U.S. that otherwise would have gone abroad."