There is a protocol description here:
http://www.jasig.org/cas/
An overview of the authentication process is here:
https://confluence.ucdavis.
There are a large number of existing client implementations here:
http://www.ja-sig.org/wiki/
On a successful authentication you will recieve the unique id for the authenticated person.
Username, name and emailattribute can be found by in the LDAP-adressbook at ldap.kth.se
http://drupal.org/project/cas
SvaraRaderaDet finns stöd för CAS i Drupal!