Esperanto translation using Apple Dictionary on OS X
First, get the English to Esperanto stardict dictionary here and the Esperanto to English dictionary here.
Then, download DictUnifier here.
Lastly, run DictUnifier and point it at each of the dictionaries you downloaded (or any other stardict format file) and they will be transformed into a dictionary in Apple's Dictionary app.
If you want to remove a dictionary, simply delete it from ~/Library/Dictionaries
The extra side benefit to this is that the standard ^⌘D dictionary keyboard shortcut will bring up a dialog that can be used for translation:
Update: I've posted the OS X dictionary files online. I'm not aware of any restrictions on distribution of the stardict dictionary or the Reta Vortaro dictionary files, though I will delete the shares if notified that there is a restriction in place.
For both of these links, be sure to click on the link that reads "Click here to start download from sendspace", as SendSpace has ads that could mislead you to download something else. Both of these links are to zip files with Esperanto to English and English to Esperanto dictionaries.
