I'm going to Japan in the beginning of February 2008. I plan to bring my cell phone, even if it won't work in Japan. (I may need it to and from the American airports.) Once I arrive in Japan, will my cell phone work, and be usable, while in Japan? And also, will I need to use a special adapter to charge my cell phone? (When I went to Europe this past Summer 2007, I did acquire and use a special electrical adapter for the purpose of charging my phone.)

If your phone worked in Europe, it will work in Japan. The plugs are the same in Japan as they are in the US - no adapter required.