If you want to keep your text messages from becoming another autocorrect disaster, GigaOM has a simple tip for typing out words you know aren't in your phone's dictionary.
When you type a word the iPhone doesn't know, it'll usually pop up a correction, which you can tap to ignore. But this can be hard to hit, especially when you're trying to type really fast. Instead, you can just add an extra letter to your word, then delete it without skipping a beat:
If you're trying to type a word that your iPhone does not know, simply type an extra letter on the end of the word and then delete it. So if I was trying to the type the word "Apple" and I knew my iPhone would not recognise it, I would type "Applez" then delete the "z" off the end of it and then can just press spacebar without the phone trying to auto-correct me.
Note that if you want the word in your dictionary, you'll want to go the official way of clicking the "x" when it tries to autocorrect your word. But if you're in a hurry, this actually is a bit faster once you get it in to your muscle memory.