Orthene (Acephate) has suffered the fate of all organo-phosphate based insecticides - usage has been banned. I haven't checked its status recently but it was available (probably stocks on hand) for limited commercial/agricultural use. All consumer level products were pulled from the shelves a couple years ago. You might be able to find it online in bulk quantities (concentrates). You might even find an online store that will ship it to you illegally as a few suppliers put the responsibility on the buyer to check if it is legal to ship to your state. I would avoid doing business with such sources.
A good place to check on the status of a pesticide is http://www.pesticideinfo.org/
A good place to check on the status of a pesticide is http://www.pesticideinfo.org/