I am planning on going to Tokyo for three months to stay at a friend's apartment. I want to earn some spending money while I am there. Any suggestions for making money? I heard tutoring students in English pays well? Do you need a visa for this? Are there part time jobs that an American on a tourist visa can qualify to do?

Teaching private lessons will fetch you around Y4000 - Y6000 per hour. You are basically a paid conversation partner. As far as legally[i][/i] working on a tourist visa, forget it. Your best bet is to find part time work in a bar somewhere that pays you under the table. Roppongi in Tokyo or America Mura in Osaka are the best places to look for this sort of thing.

You definitely need to have at least a bachelors to teach legally in Japan. If you try and teach English without it, you will be deported and possibly arrested. They will then revoke your passport, perhaps for life. So i encourage you to be careful with the decision you make.