There is a good tutorial for Adding and Updating a Table of Contents in OpenOffice’s Writer over at OpenOfficeX.

table_of_Contents

Just a note before you jump to the link – it says that you can BUY OpenOffice – but they offer unlimited support for users. Note that OpenOffice is a free software – if you buy this version, you are buying the support, which is not normally available with free versions of OpenOffice (other than through a very active community).