For those of you in Aiken, there is a Facebook group called CSRA Non-Theist Group. This link may work: http://www.facebook.com/#!/groups/CSRANT, but if it doesn't reply back or try to search for it. I don't know if they are secret or not. It is an active group.
Myrtle Beach Humanists and Freethinkers started with just three people meeting for friendship & support, and now has over 60 people on their Facebook page. I say you guys get together and see what comes of it!
David, I am in Summerville. There is a large and very active group in here in the Charleston area - Secular Humanists of the Lowcountry. website: www.lowcountryhumanists.org, FB: Secular Humanists of the Lowcountry, also on Meetup.
Also, for those with children, there is a secular parenting support group as well - the Secular Humanist Families of Charleston: http://groups.yahoo.com/group/SecularHumanistFamiliesOfCharleston/