Might be suffcient to go against the domain
libapache-authensmb - SMB authentication module for Apache/mod_perl
or you could stack up pam and use winbind to do the ticket checking.
libapache-mod-auth-pam - Authenticate web access using PAM
winbind - service to resolve user and group information from Windows NT servers
Or even just make pam check the ticket directly
libpam-heimdal - PAM module for Heimdal Kerberos 5
libpam-krb5 - PAM module for MIT Kerberos
Or just have apache do the kerberos thing itself
libapache-mod-auth-kerb - Apache module for Kerberos authentication