Strange Numbers on Caller ID?

boohiss asks: "I've been getting a lot of calls on my cell phone from '+001819'. I haven't answered them, of course. But what is this number? I've found some various explanations here and there, but nothing conclusive. There's also the story on Snopes about the famed 809 long distance scam, which may or may not be what this is. Could it be some form of cell phone spam that isn't compatible with my phone? Does anyone else get these calls, and has anyone figured out what they are?" If anyone is unfortunate enough to fall for one of these, what options do they have in terms of damage control?