So, I asked them how to get one.
to get a P-Name you have to have a talent for one of these three things:
Making Vocaloid songs
Making UTAU songs (but these have to be REALLY good C; )
you then have to make a Nicovideo account, upload your works and wait until they get at least over 100 views. (my videos just sort of got popular from there so i'm not sure of what to tell you xD) soon you should be contacted by the official producers to join their little P-Name group, if not then you can contact them.
So go out and EARN a P name before you use one.