L'entrée de caractères asiatiques a toujours été une galère sous Linux. Heureusement la situation tend à s'améliorer un peu, bien que l'on soit encore loin du tout fonctionnel. Voici comment je suis parvenu à avoir le support pour l'écriture en japonais sous Kubuntu Dapper (6.06), Edgy (6.10) et maintenant Feisty (7.04), avec SCIM et Anthy.
Update: Nick just sent me an email to put his great website to my attention. It allows you to enter a Japanese address in romanji and will locate it for you on Google Maps. So you probably want to try it before going through what is explained here.
Check out http://diddlefinger.com. Thanks for this great work, Nick!
This page links to free ressources for people studying Japanese, including online courses, online tools, software and browser extensions. There are many books and kinds of courses available in exchange of your money - however, I've got better results using the following online courses combined with the tools presented below. And it's much more fun, too.