1) File your incorporation documents. You can use a lawyer or use a website to do it yourself.
http://www.legalzoom.com/ Legal docs
Make sure that the name you are choosing is not in use already by checking the website of the Secretary of State
http://www.sos.georgia.gov/ Secretary of state
2) File an SS4 form with the IRS in order to receive a FEIN number or tax ID number.
3) Fill out an application for a State Tax withholding number and Sales tax number with the GA department of Revenue
4) Fill out an application for a DOL number with the Department of Labor
5) Fill out form 2553 if you decide to file as and S Corporation for Tax purposes