My oldest will be going away to camp for her SIXTH YEAR this summer. She loves it and looks forward to it all year long. Last year she cried when I went to pick her up.
My youngest is going for the first time this year; I didn't send her quite as young as I sent her sister -- she wasn't ready until this year, but she is sooo excited!
Most sleep-away summer camps around here are one-weekers -- in fact, it's pretty tough to locate a two week session. Typically, parents drop off on Sunday afternoon and pick up on Friday afternoon. This is true of all types of camps: scout camp, YMCA camp, church camp, etc. We also have some day-care type camps; for example, we have one nearby that focuses on all types of water sports -- I'm considering sending my two waterbugs to that camp.
I know some kids who literally go to camp all summer long, but they tend to "patch together" a summer's worth of camp sessions. They go to scout camp for a week, then band camp, then back to scout camp for a different program, then to YMCA camp.
I am not aware of summer-long camps in the Carolinas (as in, the kid stays in the same camp with the same kids all summer long).