First you need to install the emerald theme manager in Ubuntu 10.04.After installing emerald theme manager you can install themes(which is available free and available for download) for different windows effect from the given download links-
Download Emerald themes
How to Install Emerald Themes in Ubuntu 10.04
#1. Open emerald theme manager from System->Preferences->Emerald Theme Manager.
#2. Now click on import and browse to the directory where you have saved the themes(download link is given above) and click on Open.
#3. Then select the Theme and change the windows effects.(If emerald is not running then run emerald –replace command in ubuntu terminal).