It is illegal. Consumption of any human meat is illegal.
You can however import human skulls and other various body pars with perfect legality. As long as the body part has been properly dis-infected, and they know its not from a murder or what not. Example, if you want, you could go to a medical research center and buy one of the skeletons there, if they would sell it to you. You cannot however import most animal bones, due to import animal control laws.
If by some reason , you are curious about buying human skulls, I can give you a URL and e-mail to a guy who sells \'em. I won\'t post the URL here, just in case some people are grossed out by it (I sorta am.. ) .
Just PM if you need the info ( tho I\'m not sure why anyone would buy one).
