Free psd file for glassy top cover a button, open top cover, pressing button.
Demo : Please use your mouse to point onto the picture below, and click it :

The above button is made up by 3 pictures below :
1 - Glassy top is closed :
2 - Glassy top is opened :
3 - Button is pressed :
Download the PSD file from : http://2aek.com/inventory/glassy-cover-on-button.zip

If you to know the css codes for mouse hover and click to changes the pictures, please go to : http://ye5.blogspot.com/2010/12/css-mouse-click-change-picture.html