I've implemented a Japanese/English dictionary based on the free 190,000+ entry dictionary from Jim Breen's EDICT project.
* GPL-v3 freely redistributable
* Supports multi-radical + SKIP code kanji lookup
* Built in mini-IME for drafting email. Crude, but usable.
* Developed on 1.4.5 for Pixi, seems to work on the 2.1 emulators.
A warning, while this is only a 5Mb download, this baby takes up something like 45 Mb of space on your internal drive when installed. HTML-5 sqlite3 databases don't seem to be terribly space efficient. . There is a ~5 minute install process that goes on the first time you run this thing.