That's what came with my Logitech PC speakers, exactly that.
Yeah, that image I posted before looks like 3 RCA ends, but it's what they have posted. It'd be nice to get a more useful angle on it. It might be they used the wrong picture too.
Edit: I got the Logitech's to use with the 360 at first, and I didn't know they included that cable. I couldn't find the equivalent at Microcenter, so I ended up getting these to do the job:
I laughed when I unpacked the speakers and found what I needed already there.