Hello, is there any special way to search through private (password protected) forums? It seems that some forums have all their content available online (so if I go to the "cached" page, I can actually read it, without the forum asking me for a password).
THX

The only sure-fire way to search through private forums is with an internal search program built into the forum itself. Google & Yahoo won't delve into password protected content.

There are some ways but they are well off the beaten path. You can view the cached version and there are also Firefox plugins that allow you to change your "user-agent" to something like Googlebot which also works.

In terms of books see:
http://books.google.com/books?id=XKgRELiphAcC&dq=google+hacking+for+penetration+testers&pg=PP1&ots=-ANOwPs4b6&sig=9ghNI9yTdwTDHPOvRPa1Entl_ZI&hl=en&prev=http://www.google.com/search?hl=en&rlz=1B3GGGL_enUS271US272&q=google+hacking+for+penetration+testers&btnG=Search&sa=X&oi=print&ct=title&cad=one-book-with-thumbnail