This is a simple extension to pick themes. The themes scanned from your theme directory, and the user get the choice to pick one via dropbox, simple and effective... you can add some css to style things, this is CPortlet User choice (theme choice) stored in cookie.
You are more than welcome to improve it and share
Yii framework ;-)
Copy the ThemePicker directory to your extensions directory
When you extend CController... Put inside CController::init() method :
*as an alternative you can put it in beforeAction, this will also work...
In your view put
$this->widget('ext.ThemePicker.EThemePicker', array( ));