If you're interested in printing \section{<heading>} in a similar way that \section*{<heading>} would print (that is, flush left and not indented), then titlesec provides an easy interface:

\documentclass{article}
\usepackage{titlesec}% http://ctan.org/pkg/titlesec
\titleformat{\section}%
[hang]% <shape>
{\normalfont\bfseries\Large}% <format>
{}% <label>
{0pt}% <sep>
{}% <before code>
\renewcommand{\thesection}{}% Remove section references...
\renewcommand{\thesubsection}{\arabic{subsection}}%... from subsections
\begin{document}
\section{First section}
Lorem ipsum dolor sit amet, consectetur adipiscing elit. Nullam sollicitudin rutrum tellus,
eu luctus dolor commodo eu. Integer pellentesque mollis congue.
\subsection{First subsection}
Lorem ipsum dolor sit amet, consectetur adipiscing elit. Nullam sollicitudin rutrum tellus,
eu luctus dolor commodo eu. Integer pellentesque mollis congue.
\subsection{Second subsection}
Lorem ipsum dolor sit amet, consectetur adipiscing elit. Nullam sollicitudin rutrum tellus,
eu luctus dolor commodo eu. Integer pellentesque mollis congue.
\subsubsection{First subsubsection}
Lorem ipsum dolor sit amet, consectetur adipiscing elit. Nullam sollicitudin rutrum tellus,
eu luctus dolor commodo eu. Integer pellentesque mollis congue.
\subsection{Last subsection}
Lorem ipsum dolor sit amet, consectetur adipiscing elit. Nullam sollicitudin rutrum tellus,
eu luctus dolor commodo eu. Integer pellentesque mollis congue.
\section{Second section}
Lorem ipsum dolor sit amet, consectetur adipiscing elit. Nullam sollicitudin rutrum tellus,
eu luctus dolor commodo eu. Integer pellentesque mollis congue.
\subsection{First subsection}
Lorem ipsum dolor sit amet, consectetur adipiscing elit. Nullam sollicitudin rutrum tellus,
eu luctus dolor commodo eu. Integer pellentesque mollis congue.
\end{document}
This just sets the label separator between the section number and title to 0pt, as well as not printing the number. \normalfont\bfseries\Large is the default formatting for article.
\section*? Should the numbering start again at 1 or should it continue? – knut Dec 5 '11 at 21:39