Here’s a nifty trip from Lifehacker.
When typing words that are not part of the iPhone’s dictionary (such as slang or other languages), the auto-correct can be a real pain. A way to trip the auto-correct and make it stop working is to type behind a “z.” Not many words have a “z” in it so the auto-correct doesn’t even have a guess to hassle you with.
The Geek Whisperer 