Below are some links to websites that you may find helpful.  
Internal Revenue Service
Internal Revenue Service
W4 - Federal Income Tax withholding Certificate
Apply for a Federal Identification Number
New York State
New York State Department of Taxation
IT2104 - NYS income tax withholding certificate
Certificate of exemption from NYS income tax withholding
New York State Department of Labor
Social Security Verification
Posters and forms required by law to be posted in
your business.
List of required postings
US Citizenship and Immigration Employment
Eligibility Verification Form and
Social Security Verification.
Form I-9 Employment Eligibility Verification form
New York State New Hire reporting
You must report to New York State all new hires:

You can either mail a copy of your new employee's NYS IT-2104 to the
following address:

New York State Department of Taxation and Finance
New Hire Notification
PO Box 15119
Albany NY 12212-5119

or you can fax the information to :    (518) 320-1080


For more information please follow the link below
New hire reporting requirements
Links
Written Notice of Rates of Pay and
Regular Pay Day : Regulations
Apply for a New York State Identification Number