I use the PowerDot class to make presentations (such as the one in a previous post), and I have come across a nasty problem in the current testing branch of Debian (Lenny). Obviously it is bound to affect any other distro relying on Debian, such as Ubuntu.
In short, when selecting paper=screen paper size in a PowerDot .tex file, the current dvips (version 5.96.1, provided by the package texlive-bin version 2007-12) generates a PostScript file with a wrong paper size. To fix it, you can get the following file:
% wget http://tug.org/svn/texlive/trunk/Master/texmf/dvips/config/config.ps
and put it where the following command tells you:
% kpsewhich --format='dvips config' config.ps
after backing up the old (buggy) one, just in case. For example:
% mv /etc/texmf/dvips/config/config.ps /etc/texmf/dvips/config/config.ps.backup
% mv config.ps /etc/texmf/dvips/config/
This fixes the problem for me.