You can look up Japanese words in 漢字、ひらがな、or カタカナ and make word lists and flash cards right on the site. You can also view wordlists made by other people.
もえもえ。。。きゅん! ーーーーーーーーーーーーーーーーーーーーーーーーーーーーーーーーーーーー Yes, I will admit that one of the main reasons I want to learn Japanese is to be able to watch anime without subtitles. I am not ashamed. >3< Watching slice-of-life anime like K-ON! and Yotsuba&!, etc. is totally the best way to learn not only vocabulary, but also speech patterns and customs (besides, of course, actually visiting Japan). Hey, any excuse to watch cartoons!!
Some of my other favorite series/movies(かなで) らき☆すた まいひめ あずまんがいおう カウボーイビボップ まりあさまがみてる ストロベリーパニック せんとちひろのかみかくし(Spirited Away ) かぜの谷のナウシカ(Nausicaa ) パプリカ