I found a good place to memorize English words:ShanBay
There are 3 features fit me well.
Firstly,it has many word books for different kinds of people and you can chose one or severl books from it,for example,a GRE word book.This is nearly all you have to do.Eveyday when you log in,it will automatically push some new words to you,and throuth reading,writing,listing,and guessing,you can learn them well.
Secondly,you can build your own word storage. As for me,I am a programmer,so evry day i have to read more or less some english material.When i see a new IT word,I can add it to my word storage.I think this function will also help you,so long as you have to read english material.