Here are two ways our computers can talk using the router on ethernet or internet

http://www.lavasoftware.com/downloads.html#FileShare it is available as a lite and as shareware at US$25 percopy

The following is very nice and needs a key they will send for evaluation;
Timbuktu Evaluation Product. http://www.netopia.com/software/products/tb2/
the URL of the download page is included below: http://www.netopia.com/software/products/tb2/2000/pro2000_download_dl2.html
It's about U$90 per copy

the following is good for messages http://www.quickpopup.com/home/download1.html?sn=ho