Do you use the language tools on Google? Well, now you can use some of them on the iPhone. Google has put up an iPhone version of its popular Google Translate tool using the AJAX API. They even tested the amount of data the tool uses so that you know what you are paying when you use this overseas. Here is the post about the Google Translate for the iPhone:
"Google Translate for iPhone is optimized for speed, supports all of the existing Google Translate language pairs, and uses a client-side data-store on your iPhone to hang on to Google Translate for iPhone is optimized for speed, supports all of the existing Google Translate language pairs, and uses a client-side data-store on your iPhone to hang on to your past translations so you always have them at hand, even if you can't use the local data network. We wrote this using the AJAX Language API, so every time the Google Translate team updates the languages they support, the languages will automatically be added here.
I tried an early version of this interface out on my trip and it was great -- although my pronunciation wasn't. So every now and then, I would just hold up my phone to let people read what I couldn't. If you're wondering about data costs, I found that I could get between 200 and 400 translations in 1MB of data download. Although we don't charge for this service, your carrier may charge for the data usage so be sure to know what your roaming rates are. For my plan, I found that I could translate 400 phrases for less than $10 when roaming internationally.
To try Google Translate for iPhone, point your iPhone or iPod Touch web browser to www.google.com and choose the "more" tab. Or you can go directly to translate.google.com in your browser. If you are traveling this summer (perhaps on your way to Beijing?) we hope you find this useful."