One of my friends is planning to learn Japanese, so I thought I'd put together some tips for him and for other people.
If you're planning to learn Japanese, I have some Japanese-related bookmarks on del.icio.us that you might find useful. =) You might also want to check out what other people have bookmarked for japanese+language.
I particularly recommend this quick and dirty guide to Japanese, Jim Breen's WWWJDIC and the example sentence search. You can download the examples file from the FTP server for totally awesome local lookup. I wrote some code in Emacs to make this easier (and to insert random taglines into my blog posts =) ).
Good luck and have fun!