It would be nice if there were one calendar that you could watch and know of all the races in our area -- but apparently that's not possible. I can hardly keep up with just Oconee and adjacent counties. Each one of these calendars often has events that aren't listed on the others.
Running Journal (Cool magazine covering the Southeast. If you want to promote your race, you really should be on this calendar -- a basic listing is free.)
Running in the USA (another very popular one, free)
active.com (Does online registration for races. You can be on their calendar even if they aren't doing registration for you, but you have to sign up for at least a free account to submit an event.)
go-green events (Online registration and race management. Based in Spartanburg I think. Free listings.)
Terry Times (Wayne Terry does the timing for most of the races in Oconee, and many elsewhere)
SCRUNNERS.COM (this one focuses on track meets, cross country, high school and college events, though not exclusively)
Strictly Running (Columbia. Manages a state-wide grand prix series.)
www.gottarunclemson.com shoe shop in Clemson. There's a bulletin board in the store, and they have weekly group runs and such.
That should keep you up to date on our area. If a nearby race isn't on any of those, it must be a private party. Here are some further away calendars, and race timing or management links:
Classic Race Services (Northeast GA) ** BEST NORTH GA CALENDAR **
Greenville Track Club
It's About Time (race timing and management)
Race Management Systems (timing and management, site doesn't work with Firefox or Chrome browsers)
Book-Events.com (Greenville area, mostly)
Adventure Geek Productions
GO Magazine (Greenville)
Foothills Trail Ultra Runs (Trail running and ultra distance folks have a distinct "scene" from the road runners, though there is some overlap. See also Runners From Hell and South Carollina Ultras On Trails.)
Run Georgia
Cool Running
additional suggestions welcome