If you go here
http://www.pocketbookreader.com/Downloads.html and scroll down a little ways, there's a link for Sample Dictionaries. It's a compressed file, and it contains an English dictionary. It's the 1913 Webster, but it's public domain so it's free to use. Uncompress the file, and copy the dictionary into the dictionary folder on the 360. You will then be able to select it when you want to look up words. While you're in the dictionary folder, you can remove any unwanted dictionaries and only have the English one. There's another English dictionary floating around here somewhere, but I can't find the link to it now. Look through the Pocketbook threads from (I think) last summer, and you might be able to find it. There's all kinds of good info in the stickies and threads, anyway, and you'll find all kinds of things you never thought about being able to do.