Paste this line : deb http://ppa.launchpad.net/compiz/ubuntu hardy main

After that, close the software sources and reload the repositories (it will reload automatically after you close the software sources) .

The installation is pretty easy, you just need to update the compiz from the update-manager. After you update the compiz fusion, here is some new features that you might need to know:
Quick changelog:
plugins-main:
- ————-
* New plugin: Static Switcher, a simpler switcher with a moving caret instead
of moving thumbnails
* Ezoom: New Zoom Box action allows using the mouse to select a zoom region.

plugins-extra:
- ————–
* New plugin: Cube Addon, a merge of Cube Reflections and Cube Caps, adding
new Cylinder and Sphere deformations
* New plugin: Wallpaper, sets unique wallpapers per viewport. Replaces the
Background images functionality in Desktop Cube.

libcompizconfig:
- —————-
* New “internal” tag in action metadata. The tag can be used to indicate that
a binding is not a global binding.
* Added workaround to ensure that Benchmark is the last plugin
* App Switcher: Panel switching bindings moved to Bindings section

Configuration manager changes:
ccsm:
—–
* Check if an action conflicts with another plugin when enabling a plugin
* Internal action bindings will now only conflict with global bindings;
internal actions in different plugins can have the same bindings.
* Rewrote plugin overview page
* Changed native size of category icons to 32×32
* Internal code refactoring and bug fixes

simple-ccsm:
————
* Removed hard-dependency on some plugins (e.g. animation),
simple-ccsm will now be able to start without them
* New profiles: Minimal, Medium, Advanced and Ultimate
* Show which accessibility features (zoom, colorfilter) are enabled
* Cube effects (deformation, transparency, reflection) are now configurable
* Window focus animation is now configurable

If you want to try the new cylinder and sphere deformations. Open CompizConfig Settings Manager and turn on the Desktop Cube, Rotate Cube, and Cube Reflection and Deformation plugins. In General Options->Desktop Size, set the size to four horizontal. In Cube Reflection and Deformation->Deformation, select cylinder or sphere. Rotate the cube by moving the cursor while holding the left mouse button and pressing Ctrl-Alt.

And here is some screenshots of the compiz fusion 0.7.6:

Oh, yeah, I almost forgot, this is also a tutorial to enable Stack Switch.
StackSwitch tilts your desktop and windows down like a table, and flips up the selected window. Just like the screenshot up there.

StackSwith installation(type at the terminal): sudo apt-get install typeswitch

And after the installation, you can found taskswitch at: System->Preferences->CompizConfig Settings Manager. Find and enable the plugin Stack Window Switcher. The switcher can be activated by pressing Super-Tab, or Super-Alt-Tab to show windows from all workspaces. (The super key is also known as the Windows key.)

And watch this video to know more about the new compiz fusion 0.7.6 effects:

And that’s all of today tutorial about compiz fusion 0.7.6 . You can have more experiment with those software. It has a ton of effects. If there’s a problem, contact me via comments or mail. The local time now is 07.30 A.M , and I need to get to offline now. The electricity will going down and I don’t have any electricity for about 9 hours.