Example for a list using mdwlist:
\begin{itemize*}
\item First
\item Second
\end{itemize*}
The bullet symbol for the first level can be redefined with:
\renewcommand{\labelitemi}{$\bullet$}
It apparently uses a math environments symbol by default.
I would like to reduce the size of it, but font size modifiers like \tiny seem to be invalid.
\parbox[c]{.5em}{\tiny\textbullet}? It needs an extra width, but should be OK here. – Leo Liu Jan 09 '11 at 17:24