I recently learned about a website called Word Champ from Nina Lyulkun via the Learning With Computers Yahoo Group. It has an extensive multilingual vocabulary learning system. In addition, it allows users to read news from a variety of sources while allowing them to point and click on words for translation help.
Registration, which takes just a few seconds, is free. Teachers also can set-up classes for free as well, and create their own vocabulary lists.
I’ve placed the link on two different places on my site. One is on the English Themes For Beginners/Early Intermediate page under News.
The other is on my Bilingual Exercises page under Mixed.