Many of the voice commands for Dragon Dictation also work in Siri's Dictation service on the iPhone 4S. The new speech-to-text service allows users to press a microphone on the keyboard in any application and then utilize Siri's speech recognition to enter text.
Jim Rhoades of Crush Apps has made an extensive list of commands that Siri's dictation service understands:
"new line" - move to the next line
"all caps" - make the next word all uppercase
"all caps on/off" - turn caps lock on or off
"smiley" or "smiley face" or "smile face" - :-)
"frowny" or "frowny face" or "frown face" - :-(
See Rhoades' post on the Crush Apps blog for the full list of Siri dictation commands.