Sun PDF Import Extension, an OpenOffice extension introduced by Sun enables you to import the PDF documents in to OpenOffice Draw and provides the modifying capabilities. That is any ‘PDF/ODF hybrid’ file can be opened without effecting the layout properties using this PDF Import Extension. Without PDF import extension a PDF file can be viewed with PDF viewer but cannot be modified.
As you have to buy most of the PDF editors available in the market and some of free PDF editors does not support much of editing capabilities, this free open-source PDF Import Extension is very useful for editing PDFs in a better way. Though it may not support all the editing capabilities of Acrobat Professional, PDF Import extension may be kept top on most capable free PDF editors list. To know more visit http://extensions.services.openoffice.org/project/pdfimport.