How can I obtain a federal employer identification number (EIN)?
To get an EIN, file
Federal Form SS-4, Application for Employer Identification Number, with the Internal Revenue Service (IRS). If possible, file at least four weeks before you will need the number. You can also obtain an EIN from the IRS by telephone (see federal Form SS-4).
Publication 20, New York State Tax Guide for New Businesses
This publication outlines the procedures to follow and the forms to file with the New York State Department of Taxation and Finance if you are starting a new business in New York State or purchasing an existing one.