Both Ubuntu 10.04 and 09.10 use Gnome Panel on the top and the bottom for various controls, such as application launchers, a system tray, date and time display, shutdown options, task switching, etc...
Neither release has the panels locked by default, a simple right click on either reveals a contextual menu with the option "Delete this Panel" clearly visible, and in my quick test, fully functional.
Ubuntu Netbook Edition has a top locked panel by default, but I would imagine that it would be a usability nightmare trying to function without it. It is, however, possible to unlock it if you change to a standard gnome session, it takes a few tries to find a tutorial on Google, and it takes, if I recall correctly, about fifteen minutes to accomplish on one's first try.
Given a better explanation of what you are talking about, people might be able to help you further. I expect that you are referring to something else, but with the information that we have, I don't think we can help.