I'm not a current JET, but I've taken the TOEFL before. (Because 12 years of education in English AND taking the 'A' levels in English wasn't enough proof of English proficiency for certain US universities. No, I'm not bitter.) I took mine based on the old format, but I looked up the changes that have been made since then.
There are now 4 components - reading comprehension, listening comprehension, speaking and writing. It is a timed test, and each section has to be completed within a time limit (not unlike the SAT). It's also a really long test at 4.5 hours, according to the website. She's going to need to build up her stamina for that. I know I was pretty tired at the end of my test and I'm a native speaker, so it'll be even more taxing on her.
There are only internet-based tests in Japan, so she'll have to get used to doing the test on the computer. I know that preparation books are readily available from online bookstores, but I'm not sure if there are any computerized versions. You can try looking for them.
There are lots of information in the ETS website, including sample questions. (http://www.ets.org/
). There's also a great site with sample questions and tips here (http://www.englishclub.com/esl-exams/ets-toefl.htm
). You can find more information by Googling specific sections of the test. Hope all these helped. Good luck!