look in /etc/X11/xinit
in that directory you will find a file called xinitrc. this may be a symlink to another file in that dir such as:
polymorphic@constellation:/etc/X11/xinit$ ls -l
total 33
-rw-r--r-- 1 root root 321 2005-01-23 23:48 README.Xmodmap
lrwxrwxrwx 1 root root 12 2005-04-19 18:42 xinitrc -> xinitrc.xfce*
-rwxr-xr-x 1 root root 556 2003-03-16 17:59 xinitrc.blackbox*
-rwxr-xr-x 1 root root 560 2005-01-22 13:34 xinitrc.fluxbox*
-rwxr-xr-x 1 root root 559 2005-01-31 10:54 xinitrc.fvwm2*
-rwxr-xr-x 1 root root 630 2004-06-19 19:16 xinitrc.gnome*
-rwxr-xr-x 1 root root 536 2004-12-18 21:42 xinitrc.kde*
-rwxr-xr-x 1 root root 664 2005-01-23 23:45 xinitrc.twm*
-rwxr-xr-x 1 root root 788 2004-10-28 15:54 xinitrc.wmaker*
lrwxrwxrwx 1 root root 20 2005-04-19 18:26 xinitrc.xfce -> ../xdg/xfce4/xinitrc*
in that case, rm'ing the xinitrc file and resymlinking it with:
ln -s /etc/X11/xinit/xinitrc.enlightenment xinitrc (assuming you have a file called xinitrc.enlightenment in your /etc/X11/xinit directory)
otherwise, just edit the /etc/X11/xinit/xinitrc file to change what WM it launches.
