In Google Chrome you can use the Speech Recognizer app available for free through the Chrome Web Store. To use the Chrome Speech Recognizer just install it from the Chrome Web Store, launch it, then click the microphone to start taking and recording your voice. The Speech Recognizer will type out your text when you finish recording. You can then copy and paste your text to the paragraph box below the Speech Recognizer or to a document you have open in Google Docs.
Online Dictation is a free site that will transcribe your speech for you. To use the site just visit it, click on the microphone icon, and start talking. If the transcription inserts the wrong word (for example it inserted "number" instead of "mumble" when I tried it) just click on that word to replace it. You can copy the transcript and paste it anywhere you like.
