The 'contrib' repository is mentioned on FAQ/General #13: http://wiki.centos.org/FAQ/General#head-92ba307b036080a16dbffa44486cde25c081fcca but not on the AdditionalResources/Repositories page: http://wiki.centos.org/AdditionalResources/Repositories
The 'contrib' repository is mentioned on FAQ/General #13: http://wiki.centos.org/FAQ/General#head-92ba307b036080a16dbffa44486cde25c081fcca but not on the AdditionalResources/Repositories page: http://wiki.centos.org/AdditionalResources/Repositories