According to the Sega Europe official blog, Yakuza 4 is being localized and will be released in Spring 2011. No official announcement has been made for a North American release, but the game will be at E3 next week. It's likely to be announced for North America at the event.
Keep in mind that even if the game is not officially released over here, the Playstation 3 is region free and will play European discs. So either way, we be playing Yakuza 4 soon enough!
The news is certainly surprising considering it took Sega of America almost a year after the Japanese release of Yakuza 3 to even announce it was being localized. Then they released the game the same day as Final Fantasy 13, so I assumed they were simply sending the series to die here. Well I guess Yakuza 3 sold well enough to announce the Yakuza 4 localization just a couple of months after the Japanese release.
The only other concern now is the potential for cut content in Yakuza 4. As I predicted before, I seriously doubt Sega would remove anything this time considering the backlash to the cuts from the previous game. If anything, they will use "We are not cutting anything this time!!" as a marketing strategy. Either way, this is great news.