Yellowbridge is the site I use the most:
http://www.yellowbridge.com/esp the first link on that page, the english/chinese talking dictionary. You can input in so many ways including imprecise pinyin, characters you have cut and pasted, draw a character, english etc, and it gives you a whole slew of suggestions you can use to narrow down your search. The talking part is so very helpful too.
http://www.yellowbridge.com/chinese/chinese-dictionary.php