Eijiro isn’t exactly a dictionary in the strictest sense; it’s a giant corpus of sample translations, which can be very useful if you’re stuck trying to word something in English or Japanese.
I learned that when I did my research. While not a true dictionary, the big advantage of being able to look up something in the Eijiro database is that it has lots of obscure things in it. As it currently says in the Wikipedia article on it:
So I take it from the long silence that nobody here knows about how to setup a PDA or smartphone as an electronic dictionary?
Well, Eijiro can be purchased online for a reasonable price, and all that remains is to find some application for your PDA/smartphone that can read that file format, such as PDIC. However, Eijiro IS quite large, so I don’t know if you’d be able to store it on the device. You might need a memory card or such.