I don't think it'd work on phones for other places, the Japanese phones have some different functions.
I do hope it will work though, it never hurts to try! lol
I didn't see any thing on the official home page... Hmm..
According to that website you provided, it said you can download the stuff from phones, which I'm guessing will not work anywhere else other than Japan... :)
The design is very cute though! I might consider buying one..
I started playing tama when they first started in 1997, I will stop playing with them every few years,
and I do regret selling some old ones and throwing some of them away.. ;_;
I'd say keep yours safe untill another time!^^