So which is it?

You know how you hear phrases over and over and it just becomes second nature to hear them after a while? Today I was listening to the radio while running errands and I caught part of a conversation, one that I wasn't really paying a lot of attention to, until I heard a guy say, "I could care less about..."

That got me to thinking about the use of that particular phrase. Now I'm supposing when people say, "I could care less," what they really mean to convey is that they don't care. Is that what you would take away from a conversation in which someone has made the statement, "I could care less"?

So... if you don't care, shouldn't you say "I COULDN'T care less"? I mean, that would indicate that you couldn't care any less than you do at that moment in time. Doesn't that make more sense? If you say, "I could care less," that indicates you COULD possibly care less than you currently do, which means you DEFINITELY care, right? Over-analyzation? Hmmm... maybe, but it's one of those things that bugs me. Which is the correct way to say this phrase? Inquiring minds wanna know!