I saw a post about 'plecodict', but haven't a pda or iphone to try it.
I use: MDBG
http://www.mdbg.net/chindict/chindict.php
and think it is great. It shines for finding obscure words and breaks everything down so nicely when you are inputing difficult text. you can even write with a mouse.
Rather than sounding too much like a commercial, I urge you to check it out for yourself. It is also editable, so if there is a word not already combined, users can edit it. If there are a lot of Tao bums using it, the religious jargon will improve. The more people that use it the better it will get.
What do you think?
Is anything better out there?
I used babelfish and google translators for a while, but they get pretty useless if entering any sort of esoteric religious texts.