One of these changes comes in the System Preferences pane. In Snow Leopard, Apple’s own preferences were unmovable, and those additional panels that you added could only be uninstalled to remove them. In Lion you can hide or show Preference panels without deleting them entirely, allowing you to save screen space and cut out the panels you rarely use, helping you to find what you want more quickly.
In System Preferences you can click and hold on the Show All button to bring up a list of all your panels. To switch to one you just have to select it, but for now select Customise from the bottom of the menu.
2: Click to untick
You will see all the panels now have tick boxes over them. Click on the icons to uncheck them, which will remove them from the window when you click Done without deleting them forever.