Suggestions to fill out a PDF form & fax it?

[slickrcbd]

I see that OpenOffice Writer has an option to "export as PDF", but I can't get it to import one.
Is there an add-on for Office or can somebody suggest a free program to let me open a PDF file, fill out the form, then save it as either a PDF file that Acrobat 3.0 can read or something ClarisWorks 4.0 can read?

I need to fill out a form that's in PDF format and fax it in, but I don't have a fax machine. I do have a fax modem on an on an OLD PowerMac 6500/300 running Mac OS 8.6 (though I do have a 7.6 boot partition), so that would be my first choice of platform. Unlikely to find something still available for that OS.

I have Windows 98SE and Windows Vista 64 available as well, and if I can export to a format the 6500 can read with ClarisWorks 4.0 or Acrobat Reader 3 (might be 4 or 5, I forget), That would work.

I could have sworn I did this with an earlier 2.X version of Office on my old Win98 machine, but this is the first time I've tried since upgrading it to 2.4.2.