Here is the aforementioned rule using tikz with the center dot set to 1 pt. In the updated version, I filled them in and extended them to slightly more than \textwidth. You can tweak the number I divided \textwidth by in order to shorten or lengthen it. Note that it looks better with both the \fill and the \draw commands together. Without the latter, the edges are not crisp enough. [Sorry for the delay in updating. I was digging out from a snowstorm.]
\begin{tikzpicture}
\fill (0,0) circle (1pt);
\draw (0.2,0) .. controls (0.2,0.075) and (1,0) .. (\textwidth/2,0);
\fill (0.2,0) .. controls (0.2,0.075) and (1,0) .. (\textwidth/2,0);
\draw (0.2,0) .. controls (0.2,-0.075) and (1,0) .. (\textwidth/2,0);
\fill (0.2,0) .. controls (0.2,-0.075) and (1,0) .. (\textwidth/2,0);
\draw (-0.2,0) .. controls (-0.2,0.075) and (-1,0) .. (-\textwidth/2,0);
\fill (-0.2,0) .. controls (-0.2,0.075) and (-1,0) .. (-\textwidth/2,0);
\draw (-0.2,0) .. controls (-0.2,-0.075) and (-1,0) .. (-\textwidth/2,0);
\fill (-0.2,0) .. controls (-0.2,-0.075) and (-1,0) .. (-\textwidth/2,0);
\end{tikzpicture}
To use this with fancyhdr just put the above code inside \chead{} in your preamble.
Here's the output:

pgfornamenthttp://tex.stackexchange.com/a/46401/3235 but Alain Mathes mentions a license problem in the comments. – percusse Feb 08 '13 at 12:57:)– KOF Feb 08 '13 at 20:22