This is a free iPhone app that uses the same algorithm as the Dragon NaturallySpeaking software. It received excellent ratings and it supports dictation in many languages: English, Chinese, Danish, Dutch, Finnish, French, German, Hungarian, Italian, Japanese, Korean, Norwegian, Polish, Portuguese, Russian, Spanish and Swedish.
This app has a free trial so you can test all of its speech to text abilities. These include reading and writing out text messages, activating your GPS, surfing the web and calling. If you’re looking for a speech to text software that will help you transcribe full documents, this might not be the best option (since this app was not developed with this use in mind).
reQall for iPhone is a free iPhone app that converts your voice to text. its main downside is that you can only record short audio messages (up to 30 seconds long). This app has gotten mixed reviews due to bugs, that you can download the latest version for free and test it yourself.