Looking for Screen Splitting program for shell enviroment

[Joe Muller]

  Here at nos850 we do not yet have the capabilities of using a windows 
enviroment such as X Windows, so I was wondering if there are any 
programs out there that will allow one to split the screen into 2 or 3
sections with a shell process running in each one.  Ideally the user
would be able to run a process in one half of the screen, and by some
control sequence or tap of a function key, change their current shell to the
other the half of the screen, and at the same time able to see the
output of their previous process without it interfering with their
current work.  I'm sure that I'm not the first person to come up with
this one, so surely there must be such a utility out there somewhere.
Please mail all responses to me, and if there is sufficient interest I
 summarize and post.  I can't FTP so kudos to anybody who can mail me
the source.

 -Joseph Muller