Oooh Champers, nice to see you in science! I popped in yesterday and haven't left yet... they're really rather nice in here (bit clever, mind).
Anyway, in answer to your question. I've heard that about heads as well but I think I read somewhere that the mind is not actually conscious but that the nerves are still functioning for a very brief period after beheading so their eyes might move or something like that.... (Isn't there a record of this happening to Anne Bolene (sp) ).
Bearing in mind that I think this is comparable to the last twitch before the body dies then no, I don't really think that this could be a reality.
That said, I'm sure someone will be along to correct me very soon! ;0)