G'Day,
You have two options:
1. Download (free) Open Office v1.1.4 from
http://www.openoffice.org/.
Open Office v1.1.4 is the core of Sun Star Office v7, but
without formal support.
Open Office has 4 main components:
Writer word processor
Calc spreadsheet
Impress presentation
Draw drawing
Each component has a surprising degree of compatibility
with its MS Office equivalent.
Importantly (for you), Writer will open many Word documents
and has an "Export to PDF..." facility.
(If you go this route, keep an eye on Open Office v2 which is
now in Beta. This will be the core of Sun Star Office 8 - also
in Beta. You would be well advised to get Open Office v2 when
released).
2. Search Google for "Word to PDF".
You will find several commercial converters.
I use (and can recommend) both ScanSoft PDF Create and
Visage eXPertPDF v3, but there are several other good ones.
Of the two that I use, I feel that eXPertPDF is marginally better.