AFAIK, Unity can only show its bar on the left-hand side of the screen at the moment. If this worries you a lot, you can:

• try installing some dock, such as Docky, AWN or CairoDock. See http://www.omgubuntu.co.uk/2010/04/you-choose-the-best-dock-for-ubuntu-poll/ for an overview.




• Use "Gnome classic" session, which does have a panel at the bottom though it's not quite similar to Windows.




• Install "kubuntu-desktop" and use a KDE session, which may be closer to Windows experience.

Though I admit the last two options feel like a bit on an overkill for just moving the panel to the bottom :)