Yes you can go in photoshop cs5 to Edit>Preferences>Camera Raw (windows) or Photoshop>Preferences>Camera Raw (mac) and select what happens with Jpegs under Jpeg and Tiff Handling.
Automatically Open Jpegs With Settings means jpegs that have already been opened in camera raw.
Automatically open all supported Jpegs means any jpeg that photoshop can open.
If you want to get rid of the settings in any jpegs you can use Bridge CS5 under Edit>Develop Settings>Clear Settings.