You wouldn't want to use Google Translate as your sole source of language support, but it could certainly make your traveling life easier.
Check out the free app by downloading it from the Apple App Store.
From the Official Google Blog ...
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.
Read more about Google Translate iPhone App