Owners of the Apple iPad 1 and 2 won't get Siri on iOS 6 when it ships. Neither will those who use an iPhone older than the 4S. That leaves people looking for alternatives, and fortunately there are a few.
I took a look at Evi some months back, and now newcomer Voice Answer, which is US$3.99 in the App Store. It runs on any iOS device with iOS 4.3 or greater installed. The new version, just released, adds voice messaging, email dictation and calling from the iPhone contact list. The app can translate into 54 languages, update Facebook and publish Tweets. It also can set reminders, but not through the iOS