A simple solution to the annoying new 3D look of the dock in Leopard. Switch between the new 3D dock and the old 2D dock that resembles Tiger. Make hidden items in your dock slightly transparent, providing a visual cue that they are not currently active.
The 1.0 version of TigerDock for Mac is provided as a free download on our software library. The following version: 1.0 is the most frequently downloaded one by the program users. Our built-in antivirus scanned this Mac download and rated it as 100% safe. The application's installer is commonly called tigerdock.zip. The current installation package available for download occupies 2.3 MB on disk. This free Mac app is a product of Riotgames Production.
From the developer:
Is the New Dock in Leopard Annoying?
Change your dock from the new 3D-look to the old(more like Tiger) 2D-look or reverse.
And as a bonus you can make the items in your dock slightly transparent when they are hidden, so you have a visual cue that they aren't active.