Amazon.de listed Yakuza 3 for preorder today. The listing says that the title has a March 2010 release which would be a little over a year since the games initial release in Japan.
If the title does head to Europe we could probably assume that the title will also be heading to North America unless Sega pulls a Nintendo on us.
While Sega has yet to officially announce that Yakuza 3 is getting localized, all signs are really pointing to yes. 1up at one point heard from a inside source that the title was being localized as well and of course there is that Sega/Sony leak that happened a few months ago where they discussed Yakuza 3. Now stack this on top and you have quite a bit of supporting evidence.
I’d say its fairly safe to assume it is coming out eventually in Europe and North America. It is just a matter of when Sega will announce it.