User-agent: Googlebot
Disallow: /nav/

User-agent: Googlebot-Image
Disallow: /nav/

User-agent: Yahoo-MMCrawler
Disallow: /nav/

User-agent: vscooter # AltaVista Image Search 
Disallow: /nav/

User-agent: psbot
Disallow: /nav/

User-agent: DittoSpyder
Disallow: /nav/