Any eText Reader for language learners ?

Hi,

I'm looking for an eText reader with an integrated feature that would
look up foreign words either in an online translation dictionary or one
coming with the reader. So, if you would be reading a text in german
when you're a learner, you could highlight or hover over a word that's
giving you difficulty, and a little tooltip would pop-up or fade into
view with a dictionary translation in the language of your choice, or
just english, too.

Is there such a thing out there ? A few readers such as Tom's
eTextReader are cool (http://pws.prserv.net/Fellner/Software/eTR.htm),
but it would be surprising that nobody thought of implementing such a
simple feature as that. It would greatly enhance my progress in reading
and learning vocabulary.

Thanks in advance for any tips if someone knows of such a piece of
software out there. Peace.

Lysiane.