I created these images in response to an informal competition run by the FOAF community back in 2002! They are all in the public domain. Please feel free to use them to indicate your support for FOAF and the FOAF project.
Please email me at firstname.lastname@example.org if you want me to include other public domain FOAF images here.
-- Ian Davis, Apr 2008
For reference the colours used in the FOAF logo are: #9999cb (blue), #fc6866 (red), #9ecd9a (green), #fcfe9b (yellow)
Update Sep 2009: I've created a new SVG version of the FOAF logo: foaf.svg
Update Jul 2011: I've added these images to a new github project: https://github.com/iand/foaf-icons