Google just released their native translation app for iOS (iTunes download) which allows you to speak translations and hear results.

OK, this is friggen awesome!  details, below:

Speak to translate
The new app accepts voice input for 15 languages, and—just like the web app—you can translate a word or phrase into one of more than 50 languages. For voice input, just press the microphone icon next to the text box and say what you want to translate.

Full-screen mode
Another feature that might come in handy is the ability to easily enlarge the translated text to full-screen size. This way, it’s much easier to read the text on the screen, or show the translation to the person you are communicating with. Just tap on the zoom icon to quickly zoom in.

And the app also includes all of the major features of the web app, including the ability to view dictionary results for single words, access your starred translations and translation history even when offline, and support romanized text like Pinyin and Romaji.

Get it here.