There are very few reliable dictionaries online. Not everyone can afford to buy a good dictionary (usually a good one costs around 100 $/50 £ and up). I found one in pdf format. It was from free domain and under GNU license. It's quite big, has romanized and hangul words. And is very useful. I suggest to print it and bind.
Download link (Firefox users: right click and "save as" is sufficient):
Krn-Eng-Dict.pdf
