PlayStation Network is the unified online multiplayer gaming and digital media delivery service provided by Sony Computer Entertainment for PlayStation 3 and PlayStation Portable, announced during the 2006 PlayStation Business Briefing meeting in Tokyo. The service is always connected, free, and includes multiplayer support. The network enables online gaming, the PlayStation Store, PlayStation Home and other services. PlayStation Network uses real currency and PlayStation Network Cards as seen with the PlayStation Store and PlayStation Home.

Answer this question, if possible (if impossible, reply "unanswerable"): PlayStation Network is only available for PS2 and what other device?
unanswerable