Howtoforge posted a guide about enabling Compiz Fusion on an Ubuntu 8.04 LTS Desktop

This tutorial shows how you can enable Compiz Fusion on an Ubuntu 8.04 LTS (Hardy Heron) desktop (the system must have a 3D-capable graphics card - I am using an NVIDIA GeForce FX 5200 here). With Compiz Fusion you can use beautiful 3D effects like wobbly windows or a desktop cube on your desktop.

Enabling Compiz Fusion On An Ubuntu 8.04 LTS Desktop (NVIDIA GeForce FX 5200)