Mobile Phones
In Japan, more people connect to websites via cell phone (i-mode and others) than they do from personal computers...Watching people on the trains or on the street tapping out messages to their friends with their thumbs is quite amazing--especially when you consider that their keitai (cell phones) have to handle complex Japanese scripts containing 2,000 kanji characters and two syllabaries. You can read the news, buy concert tickets, listen to the latest music, and download tunes to use as ring tones; some phones even come with GPS capabilities, so you can find recommended restaurants and shops when you're out on the town.
Remember that you won't be able to use your cell phone from the U.S. if you bring it to Japan. If you're not sure that you want to buy a new cell phone, renting is another option. You can rent cell phones at the airport, but that's fairly expensive. An inexpensive cell phone made by Tu-ka can be used with prepaid cards (called "Pretty Card"), available for 3,000 yen ($27) or 5,000 yen ($46) at a conbini (convenience store). They are good for two or three months, respectively, after which you can receive calls for 30 more days. Calls cost about 100 yen ($.91) per minute.
(excerpt from p. 155)