In message <Pine.LNX.4.21.0101052332110.28559-100000@pilchuck.reedmedia.net>, you write:
> Do you know of any network chess games which I can play under standard
> Unix (X11 on my system) and play against my wife on her Windows 98's
> machine (native Windows application on her system)? (I do not want to run
> a X-server on the Windows platform.)

Take a look at gnuchess:

http://www.gnu.org/software/chess/

You can use xboard for the unix side and winboard for the windows side,
the FAQ, which is linked to on the above site has basic instructions for
how to set this up, look under:

"[D.8] Can I use XBoard to play a game of chess with another human?"

-- 
Michael Parson
mparson@bl.org