More simple method for some dictionaries: just get the debian package of the freedict dictionary you want, unpack it and go look inside data.tar.gz/usr/share/dictd. You can also install them in debian and then find them in /usr/share/dictd (the bigger the file the bigger the dictionary; so if you speak several languages, you can choose the best combination of languages).
You will find a .dz and a .index file!
For example here is the german-english dictionary:
http://packages.debian.org/sid/all/d...u-eng/download
Others:
http://packages.debian.org/source/sid/freedict
It works great with the new great LBook firmware from Ukrania:
http://lbook.com.ua/downloads/V3upda...20090409-2.rar
I just do a long press (2 seconds) of the key number 3 to use the dictionary.