"True, some outliners have become obsolete, and you will be
lucky to get programs like GNOME-Think or the once-popular KnowIt
to run on a modern distribution. But you can still choose among
OpenOffice.org, TuxCards, NoteCase, Emacs, and VimOutliner for
doing your planning.
"OpenOffice.org Writer and Impress
"OpenOffice.org offers two tools for outlining. In Writer, you
can outline by using the Heading styles. To edit an outline, press
the F5 key to open the floating window called the Navigator. Under
Headings you will find a tree view of all the headings you've used
in your document. You can expand or collapse the tree view as
needed, and, using the tools in the icon bar, promote or demote
headings. You can also reposition them on the tree, which also
repositions subordinate sections -- in other words, when you move a
paragraph that uses the Heading 1 style, all Heading 2 or 3 styles
until the next Heading 1 style move with it."