Smart FM is great. The name is strange--nothing to do with FM
radio but check it out. I love this site!
Webjapanese has some free lessons as well as lessons you must pay for.
Check this site out.
Lang-8 is a journal writing site
Edufire: you can learn one on one or take a group lesson online.
iTunes has a compilation of Japanese lessons. For Japanese grammar
check out Guide to Japanese.org
A wiki for Japanese grammar can be found at JGram.org
Rikaichan allows you to hear the Japanese words you don`t know how to
read by putting your cursor over the word to hear it.
Visit Koichi`s Japanese language and culture blog too.