Yakuza are Japanese gangsters who practice organized crime
If you want to Join the Yakuza you either have to get enrolled by a fellow Yakuza member or if you ask at the Yakuza Office. If you are a gaijin they might not let you join, unless you offer...
It may depend on which country you reside in. In the US no one could care less.
Yakuza 3 came out in Japan for the PlayStation 3 console on February 26th, 2009. A subtitled version was released in Korea the very next day.
No because the Yakuza have been wiped out by a tsunami... Rumor has it that the Mafia paid the tectonic plates to cause it.
in the Japanese underground of course