CN vortaroj

NCIKU http://www.nciku.com.tw/

http://www.mdbg.net/chindict/chindict.php

http://zhongwen.com/

http://www.chinalanguage.com/dictionaries/ 

http://dictionary.writtenchinese.com/

http://en.wiktionary.org/wiki/Appendix:Mandarin_Frequency_lists