Oh hey John, in an effort to be helpful I did some web digging... General Dynamics Robotic Systems does indeed call that pictured vessel the "SeaStalker USV"... but according to their literature it's an unmanned surface vessel.

You can check out their brochure here:
http://www.gdrs.com/about/profile/pdfs/0706MaritimeBrochureLRes.pdf

I'm gonna take a SWAG that the unmanned torpedo-sized thing is actually in the works (I work on UAVs, and all kinds of goofy stuff is in the works), but folks have mistakenly applied the name SeaStalker to it.

Hope this is helpful!

Technical quibble: either that photo is not the SeaStalker, or the text description is inaccurate. The text describes the SeaStalker as torpedo-sized, underwater, for ELINT and comms. The photo is a surface craft that's a heckuva lot bigger than a torpedo (maybe comparable in length, but it's got a lot more girth, and there's no way it's sub-launched), and judging by the mounted gun turret, it does more than radio/comms/ELINT surveillance. Some clarification of what exactly is pictured, or a correction of the text (or both) would be greatly appreciated.