Could someone point me to some (recent) documentation that would help me with decoding PAM configuration file lines like this:

auth    [success=2 default=ignore]      pam_unix.so nullok_secure
auth    [success=1 default=ignore]      pam_winbind.so krb5_auth krb5_ccache_type=FILE cached_login try_first_pass

I'm trying to get my Ubuntu box (testing 10.04 Server Beta 2) to use Active Directory, and the last step is to get PAM on the unix box to work, but I'm wary about making changes (and locking myself out) without understanding how to merge what I'm reading here with what ubuntu has implemented.