Here's a tip for users of OpenOffice, and it's also some feedback
for the developers about an improvement suggestion that's a result
of some further thought about this (that is mentioned afterward).

Refer to attached images:

  oo - links in the contents page - 1.jpeg
  (Where to insert the bookmark)

  oo - links in the contents page - 2.jpeg
  (List of bookmarks in the navigator, also
  showing the contents page
  where they have been dragged to)

  oo - links in the contents page - 3.jpeg
  (An improvement might be to implement
  this functionality into the
  index-and-tables for table of contents,
  something like the 'hyperlink'
  button except to automatically create
  in-document hyperlinks in the
  correct spots that will work
  when exported into PDF form)

When creating bookmarks for the table of contents, place the cursor on a blank line (thus on the left), which is located on the line before the heading. Then select "Insert->Bookmark". Then bring up the navigator,
find the "Bookmarks" category, and drag the bookmark onto a line on its
own in a contents page (set a blank page aside for this by doing 'Insert->Manual Break') at the top of the document.

This will result that, clicking on a contents page link, in the generated PDF file will place the cursor at an appropriate position.

If instead, the contents bookmarks are created by dragging from the
'Headings' category in the navigator, then the PDF file links will
not bring the cursor to the correct place in the document (it's too
far to the right). Therefore, using the strategy just mentioned above
(of creating bookmarks first), is the present solution for getting
contents-page "in-document" links to work correctly
(and look right) in the PDF file.

An improvement suggestion for OpenOffice is, to implement the
capability for links to be able to be created in contents pages
(index and tables). I noticed the 'hyperlink' capability however
(as far as I can tell) this does not appear to create links into the
document itself, to the various headings, from the contents page.
If such a feature is implemented then, it is also worthwhile to
consider the points mentioned above, in particular, the need for
the "effective bookmark" to be on the line above the heading line,
so that when the PDF is generated, clicking on the link will move the
cursor to an appropriate spot.

"If" the link was not on a blank line above the heading line, for
example if it was to the left of the heading text, then
this is not in line with the left of the document (due to indenting
of the header), so some of the leftmost text of the document would
not be "on screen" in the PDF viewer, and the cursor position would
thus not be correct.

Though in fact, I've done it so it is so it works.

This discussion may be of use to the developers of
"OpenOffice", in feedback for continual improvement of the product.
Also it may be useful for users of OpenOffice, as a current method for creating a table-of-contents containing links into the document,
which are in the correct 'visible' place, when exported into PDF form.

Note: See also
http://www.openoffice.org/issues/show_bug.cgi?id=62262
(someone else submitted), however this is not quite the same thing
because here the discussion is about where exactly, the link will
take the cursor to, when clicked on, so that it is at the correct place
in the PDF (it always does go to the correct place, if clicked in OO
itself).