Features:

• Customisable title
• Customisable button text
• Choose between text button or image button
• Customisable margin between button and text box
• Choose between small or large image buttons – small image button is designed to be used with a negative margin to place the search button inside the text box
• Info boxes in the admin area explaining everything
• Change the default images for your own, with optimum margin for ‘inner button’ case dynamically calculated and displayed in the admin area

This is based on the rather obviously named Search Widget with Title, and has been fully tested on WordPress 2.7.

So, here it is…Advanced Search Widget

Instructions: Unzip the download, upload the directory within to your plugins directory.  Then, activate the plugin and add the widget to one of your sidebars.