End of 2008??

Verizon wireless announcesed they will allow hardware and software from other companies if the hardware and software meet Verizon's standards..
Check this news..
http://www.coxwashington.com/hp/content/reporters/stories/2007/11/28/VERIZON_OPEN28_COX.html

I am not sure the networks in Japan.. But many Koreans use CDMA.. so they can bring korean phones to the verizon networks..
Sorry, T-Mobile is GSM network.. Maybe, Apple iPhone, a GSM Phone, can use japanese but you need to hack the phone to use it in T-Mobile network and typing in japanese.. This is avoiding hardware warranty..