Useful tools for learning Chinese

http://www.chinesetools.eu/ a beautiful and practical website

http://pinyin.info/tools/index.html pinyin.info
Convert Hanyu Pinyin to zhuyin fuhao (bopomofo)
漢語拼音轉換至注音符號 / Hànyǔ Pīnyīn zhuǎnhuàn zhì zhùyīn fúhào
Convert zhuyin fuhao (bopomofo) to Hanyu Pinyin
注音符號轉換至漢語拼音 / zhùyīn fúhào zhuǎnhuàn zhì Hànyǔ Pīnyīn

http://www.xuezhongwen.net/chindict/chindict.php an excellent dictionary