I actually just contacted one of the main companies that do it in North America.
The process is called "Hydrographic Printing."
It's not as simple as acquiring a stencil and putting it on - the process appears complicated enough to require sending it out to someone to do it.
The material used (the hydrographic film) is like one of those breath mint strips that you put on your tongue, and then it disolves. The sheet is literally an "ink sheet" with the pattern you want applied.
It's placed on to a surface of water, where it becomes a thin film of ink floating on the top - at that point, the prepared object (requires prepping, cleaning, sanding, and priming) is then dipped in to the now-floating ink, where it is then secured and cured.
Lakota Industries is the company.
http://www.cryeprecision.com/liquidCam.asp
^^^ That link points to Lakota Industries - at the top of the Lakota Industries page, you'll find the email link you'll need to contact Dick Williamson. Surf that page and you can also see images of the production area where the process is performed.