I submitted two iPhone applications to the iTunes App-Store: KTDict C-E and KTDict C-D. The first is a Chinese-English dictionary, the second a Chinese-German dictionary.
They are based on the following components:

• The excellent dictionary data of CC-EDICT (over 70.000 entries) and HanDeDict (over 120.000 entries). I used these great dictionaries over the Internet for many years. Fortunately, their licenses allow to include them into own dictionary software.
• The Chinese hand-writing recognition build by Apple into iPhone OS
• Fast indexing and search technology implemented by myself, which provides fast “search as you type” results.

I am using both programs myself several times a day and almost cannot imagine how to get along without. They should be available in the App-Store is in ~two weeks.