Don't see that this has been posted before...Sorry if it has!
Kindlefish  -   
http://kindlefish.t15.org/    - languge translation site for Kindle.  It's a 'front end ' site for google translate which doesn't work well on Kindle browser...I just tried it and it is very cool!!  Here's a link to a description and review-  
http://www.wired.com/gadgetlab/2011/...al-translator/  
EDIT:  Currently for 3G on 3.1 (and a patch for DX), not K2 or K2i ....Bummer 
EDIT: 4/5/2011   Now works with the K1, K2, and DX.....very cool!