How to remove/add bottom and top bar

I like to use Docky in my Ubuntu 10.10. i like to remove the top and bottom Ubuntu bar.

Also i like to know how to revert back (bring it back)

Hey there Raj, this is an easy one to answer:

Open a terminal and run gconf-editor.

Go to /desktop/gnome/session/required_components/panel and blank it (get rid of gnome-panel in the key).

Make sure Docky (or whatever other dock you might like) is set to autostart, then log completely out and back in. Your panels should be gone, your dock should not! Reversing this is as simple as re-adding gnome-panel to the /desktop/gnome/session/required_components/panel key.