Here’s a list of Tips and Tricks for Siri:
How to send E-Mails with Siri the Easy way
How to send notes to Evernote using Siri
How to update your Facebook status with Siri
How to open Applications with Siri
How to post to Google+ with Siri
How to get Siri to call you something else
How to search Google, Yahoo or Bing with Siri
How to use Remember the Milk with Siri
How to prevent Siri access on a locked, passcode protected, iPhone 4S