I live in Georgia but did not work in Georgia in 2008. Do I need to file Georgia state taxes since my employer did not withhold Georgia state taxes?

If you are present in a state, then any income earned during this period, must be reported to the state.

This is for Georgia: To your resident state, you must report your worldwide income for the year.
Read: http://taxipay.blogspot.com/2008/06/working-in-two-or-more-states.html