Hi all,
The question came up a few times this year and it's not clearly documented, so thought I'd finally summarise things for you.
Here is the latest pop-up banner:
http://svn.osgeo.org/osgeo/marketing/unitone2009/pop-upbanner2.5.pdf
More info on logo is here:
http://svn.osgeo.org/osgeo/marketing/guidelines/v2/branding_guide.pdf
The two proprietary fonts used in some of our material are included here:
http://svn.osgeo.org/osgeo/marketing/logo/fonts.zip
The files have been sitting elsewhere in SVN for a while but not documented.
Hope this helps answers some of the past questions.