"I could care less" used to be used only with sarcasm, but has begun to become widely used in the US. Technically, "I could not care less" is the more correct, for now.Utterly unrelated side question alert...
Which version is correct in your locale?
Here, it's "could not care less", but I've heard "could care less" meaning the same thing in a fair few imported TV progs/films.
Just a curiosity.