If you have one or more permanent, temporary or part-time workers, you must obtain an employer identification number from your state through which you pay unemployment compensation and other payroll taxes.
General overview of tax entities http://www.ss.ca.gov/business/tax.htm
Employment Development Department (888) 745-3886 in the U.S.
http://www.edd.ca.gov/taxreg.htm
http://www.edd.ca.gov/taxloc.htm (for a listing of local offices by county or city)
Franchise Tax Board (800) 852-5711
Illinois Employment Security (800) 247-4984 in Illinois or
(312) 793-4880
http://www.ides.state.il.us/employer/uitax/index.htm
http://www.ides.state.il.us/
Division of Employment and Training (DET) 800-392-6089 within MA or
(617) 626-5075 or (617) 887-6367
http://www.dor.state.ma.us/
http://www.detma.org/employers/simplify/chapter2.html