Here are samples you can use to alter the page size/orientation and base font size:
\documentclass[10pt]{article} \documentclass[11pt]{article} \documentclass[12pt]{article}
\documentclass[a4paper,12pt]{article}
\documentclass[letterpaper,12pt]{article} \documentclass[letterpaper,landscape,12pt]{article} \documentclass[letterpaper,landscape,12pt,twocolumn]{article}
The geometry package can issue the commands necessary to ensure the correct size is used. If geometry is used when a document is being processed by either PDFLaTeX or VTeX, it will set the neccesary dimensions as a matter of course. If the document is being processed by LaTeX on a TeX or e-TeX engine, there are two package options (dvipdfm and dvips) which instruct geometry which \special commands to use.
So, the resolution of the problem is to add
\usepackage[dvixxx,...]{geometry}
(where dvixxx is your current favourite DVI driver), and the document will run correctly with any of LaTeX (whether or not run on VTeX) or PDFLaTeX.
E.g.,
\usepackage[dvips,dvipdfm]{geometry}