Hi Shaun,
The good news is that Argo Navis works in conjunction with every
known planetrium program that offers the ability to interface to
a telescope.
As mentioned by others, Cartes du Ciel is available for free
download, operates on Windows and interfaces with Argo Navis.
If you consider running Linux, which itself can be downloaded
for free (for example, see
http://fedoraproject.org/ ), you
might then consider running KStars (see
http://edu.kde.org/kstars/ ) along with the INDI interface (see
http://indi.sourceforge.net/index.php/Main_Page )
Another consideration, again to run on Linux, is Xephem. (See
http://www.clearskyinstitute.com/xephem/ )
So not only can you obtain some excellent free planetarium
programs, you can also obtain for free an entire operating
system on which it runs along with thousands of other freely
loadable utilities, which, as far as value for money goes, is
pretty hard to beat.
Keep in mind that not only is Argo Navis designed and
manufactured in Australia, it has the requisite regulatory
approvals to be sold here. Always look for the C-Tick logo.
Best Regards
Gary Kopff
Managing Director
Wildcard Innovations Pty. Ltd.
20 Kilmory Place
Mount Kuring-Gai NSW 2080
Australia
Phone +61-2-9457-9049
Fax +61-2-9457-9593
sales@wildcard-innovations.com.au
http://www.wildcard-innovations.com.au