To edit the author (or other metadata) on an existing PDF, you'll need a program like
BeCyPDFMetaEdit (which is free). (Acrobat Pro will also allow this, but it's not remotely close to free.)
OpenOffice should have a way to establish the author when creating the file. In Word (2003), it's under the File-->Properties menu; you can place the document title (different from filename, if desired) and author name. I'd expect OpenOffice to have a similar feature.