Brands of the World - Open source database of brands vector logos
Worldvectorlogo - Worldvectorlogo has vector logos of brands you love.
LogoSear.ch - Instant search through 200K+ SVG logos from 100+ sources
Seeklogo - Seeklogo is a repository where you can search from 400,000 plus vector brand logos and logo templates.
All Free Download - Best free download resource for designers
Clker - Royalty free and public domain clip art.