Curses is the right word. It is a library (in Unix at least,
you didn't say your platform) that allows you to do full-screen
manipulation. See the
Curses module for more details.
I have never programmed with curses, so I don't really know
how well it works from Perl.
Update: See also these nodes: Curses Help and
How can I use curses with Perl?
--ZZamboni