Microsoft standard IME works perfectly for this purpose.
For the rest, well, the keyboard inputs hiragana or katakana (depends on the setting) when pressing the Space bar after the user entered a word proposes the possible kanji matching the hiragana/katakana. In a nutshell.
http://www.physics.ucla.edu/~grosenth/jwpce.html
JWPCE works even for computers lacking the East Asian files, and it doesn’t requires installation, too.
Japanese IME is standard since XP, though. Granted, you need to install them but it’s just a matter of install options, meaning not a problem at all.
MS Word supports Japanese word processing when you enable East Asian fonts in Windows. MS Office products for all countries is the same version… it’s just what default language Windows is set too that defines which country version is installed.
Last I checked though, Vista kinda changes that, since only Ultimate supports multi-language straight out the box… other versions have to get third party installs (or hacked).
[ 08-08-2007, 08:43 AM: Message edited by: Nargrakhan ]
Late but just coming back after my busy summer.
Japanese computer keyboards, cell phones, and other assorted electronic writing tools are set up so that a Japanese person can input a Hiragana character and choose the appropriate Kanji after they are finished the word.
Most computers and cell phones do this automatically and they can just press the “space bar” to go through a list until the appropriate Kanji appears.
Computers and cell phones here are set up with both Romaji, English letters, and Hiragana on the keys. You press a button labels “Katakana”, “Hiragana”, and “Romaji” to switch back and forth between the scripts.