There are many sites nowadays where you can learn Japanese quite painlessly. There are even some where you can play games to learn how to read kana and kanji! Here are a few of them:
Learn Hiragana and Katakana
This site contains more than kana games. It also has kanji games and a japanese test, with much more!
Japanese Pod 101
This site has culture classes and many free lessons on various levels.
Tamarillo.net Go to this site to find another hiragana game!
This has a helpful hiragana game!