Don’t have a iOS4 with Apple Siri? No worries! we have the second best thing.
Dragon Dictate is an app for iOS devices which is powered by Dragon Naturally Speaking software. On desktop PC this voice-to-text software is industry favorite for dictation as well as for assigning commands to your voice but it does cost a hefty $100 for home version or $200 for pro version. On iOS on the other hand this software comes for free. Do note that this is no Apple Siri, so don’t expect it to “do stuff” with your voice commands; but you still can dictate voice-to-text messages to be sent via sms / email or to update your social network statuses.
If you are not in line to get an iPhone 4S then this is the closest (legit) thing you can get to Siri. I just hope that in future version they add integration to assign commands to your voice cues too.
Grab the app for free @ iTunes