Check out Aldo Calpini's chres.pl. It gets\sets the screen settings.

You probably already know this, but this method will not work in a CGI environment - i.e. you can't get the resolution of a remote user's screen via a webpage without a client-side script such as javascript. But I'm the wrong person to ask about that :)

Update: Aldo's site appears to have changed since I was last there - and I can't find anything related to perl. The above URL is the same one listed for him on CPAN. ?

Simon Flack ($code or die)
$,=reverse'"ro_';s,$,\$,;s,$,lc ref sub{},e;$,
=~y'_"' ';eval"die";print $_,lc substr$@,0,3;