Sony has ceased shipments of the PlayStation 2 console in Japan, according to Famitsu (translated via Kotaku). The console was released in Japan way back in March of 2000 and has sold 21 million units in region as of December 23. Globally, the system has sold 153.6 million units since launch until the beginning of 2012.
Users in Japan can still purchase new PlayStation 2 systems, but once the stock is gone, it's gone.
There's been no additional word of the PlayStation 2 reaching end-of-life in other regions.