There are a lot of great travel information sites out there on the old internet. Trip Advisor, Frommers, and others provide a lot of information for nearly any destination. I’ve gotten a lot of information for Japan from those sites and various books, but a site that needs to be recognized is http://www.Japan-Guide.com.
This is a very good site that has information on everything not only in Tokyo, but the other large cities in Japan. It has tips on transportation, tourist sites, and background information on locations so when you are planning a trip, you know what you are searching for and know more a little something. Japan-Guide is a great site and I recommend people take a look at it and make use of the valuable information.