Wonder if someone could help me resolve this minor annoyance.

I like to view unix online manual pages in emacs (using M-x man). But one
annoying thing is that the buffer is split vertically (into top and botton
frames) and the man page shows in the bottom frame. As far as I know xemacs
does not do this by default. In xemacs the man page buffer simply replaces
the current buffer and occupies the entire frame. How can I get gnu emacs
to do the same thing?

thanks.