I found this good article on what an "About us" page should contain on a website. Main conclusion: it should clearly state what the company does. Who would have thought??
About Us Information on Websites (Jakob Nielsen's Alertbox):
About Us Information on Websites
Summary:
We found a 9% improvement in the usability of About Us information on websites over the past 5 years. But companies and organizations still can't explain what they do in one paragraph."
