\documentclass{letter}
\usepackage{helvet}
\usepackage{epsfig}
\begin{document}
\address{
\psfig{file=cmuwordmark.ps,scale=0.40}\hfill\begin{tabular}{l}\bf{School of Computer Science}\\Carnegie Mellon University\\
5000 Forbes Avenue\\Pittsburgh, PA 15213-3891
\end{tabular}}
\signature{Name of Sender\\Title}
\begin{letter}
{Name of Addressee\\
Title\\
Company Name\\
Stree Address\\
City, State ZIP}

\opening{Salutation:}

This letter demonstrates the \LaTeX{} letter document type
using the CMU Wordmark. 

But things are in the wrong font.  The logo is correct.
But the few standards that do exist really want the department
and the other tidbits in the header to be in Helvetica.

The way I interpret the LaTeX philosophy:
The normal is a Serif font.
Any reason for wanting a sans serif font is questionable.
SansSerif can be obtained with \verb+\+sf .
To globally request a SansSerif font, like Helvetica, implies
that you are doing something wrong.

This is a work in progress.
It is  not yet finished.
If you use it, you'll probably be doing the wrong thing.

\closing{Complimentary Close,}

\end{letter}
\end{document}
