Even though Twitter is integrated throughout iOS 5, there's one would-be-awesome feature missing: updating Twitter with Siri. If you ask the fine lady to "Update Twitter..." she politely responds, "Sorry, I can't help you with Twitter."
At least, that's what she thinks.
After some tinkering, I set up Siri on my iPhone 4S to not only update Twitter, but Facebook, too. Now when you're driving, on an evening jog, or need a break from the keyboard, you can speak your status updates instead of typing them.
Follow these steps to get started:
Step 1: Set up Twitter
Text "Start" to 40404 (U.S. only; find your country's short code here). You'll be asked for your username and password. When you complete the process, add the short code (40404) as a new contact, and name it Twitter.
Step 2: Set up Facebook
Text "Hello" to 32665 (U.S. only; find your country's short code here). Click the link in the reply and finish the setup process in your mobile browser. When you're done, add the short code to your address book and name it Facebook.
Step 3: Update Facebook or Twitter with Siri
Now you can start updating Twitter and Facebook using Siri. Activate Siri (long press the Home button) and say "Send a text to Twitter [your status update]" or "Send a text to Facebook [your status update]". Once you confirm the message, your update will be posted.