FORM W-8BEN - Certificate of Foreign Status of Beneficial Owner for United States Tax Withholding
Generally, a foreign person is subject to US tax on its US source income. Most types of US source income received by a foreign person are subject to US tax of 30%. A reduced rate, including exemption, may apply if there is a tax treaty between the foreign person’s country of residence and the United States. The tax is generally withheld from the payment made to the foreign person.
Fill-In Form W-8BEN - http://www.irs.gov/pub/irs-pdf/fw8ben.pdf
Instructions for Completing Form W-8BEN