Korea has its own NGage like 3D gaming phone with the funny name GPang.
KTF is the provider which offers a Samsung made 3D gaming phone (SPH-G1000) called GPang. Game play looks quite ok on the 2.2 inch screen, it's no PSP though.
BetaNews has some photos and AkihabaraNews has a link to a cool video showing the KTF commercials for the GPang.
KTF has a web site (Korean) for its GPang gaming service.