Thank goodness there’s an app for this. One of the most handy features ever. I hate the auto-rotate when it does it for the home screen and for aldiko, but I would really like it to be there when using Astrid or Messaging since the landscape keyboard is much more convenient to use on my 3.2 inch screen.
Smart Rotator. Just download it from the market. Dead easy to use. Long press the app in the list and select to turn the feature on or off.