You could have downloaded ToggleDock 1.0 for Mac from our application library for free. The application lies within System Tools, more precisely System Optimization. The actual developer of this Mac application is brunerd.
From the developer:
ToggleDockwill quickly and painlessly switch your Dock back and forth between styles until you've decided on a style that fits! This app leverages the capabilities of the revamped Property List Suite in Leopard's Applescript. No messy interface: Double-click and it just works!
You may want to check out more software for Mac, such as TransparentDock, Visage Login or DiskFire, which might be related to ToggleDock.