User-agent: Googlebot
Disallow: /forums/*?action*
Disallow: /forums/*sort=*
Disallow: /forums/*msg*

User-agent: Slurp
Disallow: /forums/*?action*
Disallow: /forums/*sort=*
Disallow: /forums/*msg*

User-agent: *
Disallow: /forums/index.php?action=