I found some today inside too. Have you had alot of rain? Usually if you find carpenter ants you're in trouble; there's a nest in the wood somewhere. We've had alot of rain so I'm *hoping* that they are just trying to find dry ground. If it dries out and I still see them, I'll call an exterminator. The sooner you find the nest and get rid of them, the better.
Is there a tree overhanging your house? They could be coming to visit via the tree...otherwise, make the call.