Speech recognition software can be a great solution for people with keyboard-related RSI, or those who like to capture their thoughts with a voice recorder. As Lifehack.org points out, commercial software (like Dragon Natually Speaking) can be expensive. But he offers a free solution - Windows Vista has in-built speech recognition software.
This post runs you through how to set up Vista's SR program and train it to accurately transcribe your voice into text. He also includes some general tips for using speech recognition.
How to Use Windows Vista Speech Recognition [Lifehack.org]