Howtoforge posted a guide about enabling Compiz Fusion on Ubuntu 9.10

This tutorial shows how you can enable Compiz Fusion on an Ubuntu 9.10 (Karmic Koala) desktop (the system must have a 3D-capable graphics card - I'm 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 9.10 Desktop (NVIDIA GeForce FX 5200)