CB-like Messages Through My Computer?

[-Skeme-]

I received the first message about 4-5 months ago maybe. They come like once every 3-4 weeks and are only about 4 seconds long. Not very often. They sound like somebody talking through a CB, if anybody here has used one.

The messages are very vulgar and the voice is usually the same. Messages include:

"Shut the [censored] UP"
"Yeah, he's down there begging for someone to [censored] him in the ass."

And a few others I can't remember. I'm used to them by now, but I'm wondering how in the hell am I receiving these? Is this some form of Spyware or what? I know they aren't from a CB, but what are they?

I am not making this up, by the way. Anybody else have them?