straight from wikipedia :P
"[edit] Legality
Body armor is legal in most countries, one exception being Australia, where body armor has been prohibited for some time.[46] The late 19th century Australian outlaw and folk hero Ned Kelly is famous for his iconic home-made armor, which he used with mixed results. While the steel armor worn by Kelly defeated the soft lead, low velocity bullets fired by police Martini-Henry rifles, it greatly restricted his movement.
United States law restricts possession of body armor for convicted violent felons. Many US states also have penalties for possession or use of body armor by felons. In February 1999, the late Russell Jones a.k.a. "Ol' Dirty Bastard" was arrested in California for possession of body armor by a convicted felon. In other states, such as Kentucky, possession is not prohibited, but probation or parole is denied for a person convicted of certain violent crimes while wearing body armor and carrying a deadly weapon.
Canadian legislation makes it legal to wear and to purchase body armor such as ballistic vests. However, there are current proposals to the legislation to make it illegal to wear such body armor during the commission of a criminal offense"
http://en.wikipedia.org/wiki/Bulletproof_vest