our company was established last year, we currently have some US customers. Coz the material's prices are quite high now. so, we are going to find our sources in another country such as Brazil but i dont know about Brazil's import tax to US. Beside it, i heard that import tax from Brazil to US reduce to zero (means duty free), is it true? if true, then wat kind of products import from Brazil to US? any ideas? any tax information about new issues from Brazil tax?? Thanks in advances.

Because of the General Preference System, many products can be bought from Brazil to the US with zero import tax.
Brazil is specialized in construction products,  footwear, cosmetics, furniture, dress wear and textiles, machines, food products and beverages, mineral products, jewelry and precious stones and metals, commodities like sugar, soy and coffee beans, electronic products etc.

In time: the correct name for the agreement is General System of Preferences, or GSP.

My suggestion is to start at this page:

http://www.customs.gov/xp/cgov/trade/basic_trade/

Here you will find the basic information on how to import to the US.

For Tariff, visit: http://www.usitc.gov/tata/index.htm

Go to : http://www.usitc.gov/tata/hts/bychapter/index.htm find: http://www.usitc.gov/tata/hts/bychapter/index.htm

It would be also important for you to locate a reliable supplier. Start by contacting the SECOM section of the Brazilian Embassy in Washighton, DC