I always struggle with this because I am always to stupid to write down what I did :o). This time I have decided to write it down.

I am always drawn to the xf86config program as a way to configure X but that is a complete red herring. To configure X use:

dpkg-reconfigure xserver-xfree68

Answer about a million questions and then sit back basking in the glory of a resolution greater than 800x600.