According to Japanese gaming magazine Famitsu (via Kotaku) Yakuza 3, 4 and 5 are being remastered for the PlayStation 4. At this point, however, the games will only be available in Japan, though it is likely they will be released in the west at some point in the future. The games will retain their original art styles and gameplay, but will run at 60 FPS and 1080p.
Yakuza 3 is expected to be released on August 8th in Japan.