Add Japanese to MS Word

I work at a High School that has just started teaching Japanese as a foreign language. The teacher wants Kanji installed in MS Word on one of our labs. We are runnin XP Pro and MS Office 2003.

I have never done this before and I am not sure where to start.
Can someone give me a brief outline of what steps I need to take and any addition software I need to get from MS to do the installation?