Need help understanding or translating words while reading?

If so, you really need to use Lingro.
This is a really great little utility which you can add to the personal bar of your browser (I added it to Opera 9.50). Then activate it to get a dictionary explanation of whatever word you click on. You can also translate the word into a number of languages including french, Spanish, German and Polish. Unfortunately Portuguese isn't yet included.
I'm absolutely sure I'm going to use this.