Proper dictionaries are almost always better than their online counterparts, so I would suggest getting a good "physical" dictionary, but for online.. there is, as @azalea said,.. cantonese.sheik, but another nice up and coming site is www.zhongwenlearner.com.. its cantonese dictionary JyutDict is open source and translations are available for Cantonese-English, Cantonese-French and Cantonese-German.it also has input methods and a nice annotation tool. Hope this helps.

The cantonese dicationary and annotation tool on www.zhongwenlearner.com can speak the words back to you. Maybe that can help also. :)

Try the annotation tool at www.zhongwenlearner.com.. it can annotate with jyutping and also speak the words back to you if you want.

www.zhongwenlearner.com has a Jyutping input method you could try

www.zhongwenlearner.com has an open source cantonese dictionary and its annotation tool can speak the words back to you.