\documentclass[a0,landscape]{a0poster}

\usepackage{mathptmx}
\usepackage[scaled=.90]{helvet}
\usepackage{courier}
\usepackage{postercols}
\usepackage{flowfram}

\setlength{\vcolumnsep}{\baselineskip}
\setlength{\columnsep}{\vcolumnsep}

\Ncolumntop{static}{4}{4in}
\setstaticframe{1}{label={title}}

\newlength\offset
\setlength{\offset}{5in}
\addtolength{\offset}{\vcolumnsep}
\computeflowframearea{2,3}
\addtolength{\ffareaheight}{-\offset}

\setflowframe{2,3}{y=\offset,height=\ffareaheight}

\newstaticframe{\ffareawidth}{5in}{\ffareax}{0in}[table]
\setstaticframe{2}{clear}

\setallflowframes{border=plain}
\setallstaticframes{border=plain}

\title{A Sample Poster Created Using \LaTeX}
\author{Nicola Talbot\\
School of Computing Sciences\\
University of East Anglia\\
Norwich, Norfolk. NR4 7TJ
\and
Gavin Cawley\\
School of Computing Sciences\\
University of East Anglia\\
Norwich, Norfolk. NR4 7TJ}
\date{}

\begin{document}
\begin{staticcontents*}{title}
\maketitle
\end{staticcontents*}
\thispagestyle{empty}

\section{Introduction}

This is the main body of the poster.

\subsection{A Sub Section}
Here's a sub section that references the wide
table, see Table~\ref{tab:wide}.

% this just fills the empty columns
\framebreak\mbox{}\framebreak\mbox{}\framebreak\mbox{}

\begin{staticcontents*}{table}
\begin{statictable}
\caption{A very wide table that spans two columns}
\label{tab:wide}
% table contents
\end{statictable}
\end{staticcontents*}

\end{document}