Hi Calvin,
The logo, brochures, posters of OSGeo are available at
https://visibilitycommittee.osgeo.org/servlets/ProjectDocumentList
More info at
http://wiki.osgeo.org/index.php/Operate_OSGeo_Booth
I have marked a CC of this mail to the
OSGeo Promotion_and_Visibility_Committee
Bye
Venka