WinTrans takes advantage of the support for transparency that was introduced in Windows 2000, enabling you to easily make any window transparent.
It doesn't require installation and displays an icon in the system tray, from which you can select the window you want to apply the transparency effect to.
You'll be able to set a different degree of transparency to each window separately (from 0 to 255) or pick up a color in that window that will be considered to be transparent.
A light transparency degree can be useful to keep track of a background task while you're working on other applications.
Unfortunately, transparency effects are lost as soon as the program is closed, so you'll have to leave it running all the time if you want to keep them.
Also, the program immediately applies transparency to each program you launch, without even asking first.
With WinTrans you can apply transparency effects to any active window or applicacion.