Stardock has released the first beta of a new program called StyleVista. StyleVista allows Windows Vista beta users to alter the existing "Aero glass" interface to have different opacity levels and different colors.
By default, Windows Vista's new user interface has semi-transparent title bars and borders. While it looks quite cool, it is not currently configurable. StyleVista enables users to change both the color and opacity (how transparent the title bars and borders are) of the GUI for the active and inactive window.
StyleVista is not similar to Stardock WindowBlinds which can change the actual skin of the GUI. It alters the existing GUI. Stardock may make some of the features in StyleVista part of WindowBlinds 5 which is due to go into beta next month.
StyleVista is a free and can be downloaded at www.stylevista.net.
Screenshots:

Download: http://www.stylevista.net