The MIR Translator app, borne out of a school project, turns your N900 into a handy translation tool that covers over 30 international languages. All you do is click a picture of the text, select the phrase you want to translate, select the to and from languages and wait for the app to work its magic. Just the kind of app I needed when I was in Hong Kong, traveling with my N900 and trying to order off a incomprehensible menu.
If the recognition is erroneous, the user is able to correct the recognition via manual segmentation, manual thresholding, and manual candidate selection. If that sounds complicated, the developer has an excellent demo and how-to video.
The app is available from Extras-Devel repositories, if you don’t know what that is, have a look here.
Hat tip to @alextootchie.