http://search.cpan.org/src/FELICITY/Mail-SpamAssassin-3.0.0/ldap/READMEThe short of it is that the admin needs to add the SpamAssassin schema to ldap, they provide you with connection details, and you use the SpamAssassin module to push out the info using those connection details. In fact, it's a safe bet that the user has LDAP Users and Groups configured properly prior to this step, so you could just do a cursory check that they have the SpamAssassin schema set up, if not, ask them if it's okay to do so, do it, and use those connection details for SA.
MySQL isn't so different.
http://search.cpan.org/src/FELICITY/Mail-SpamAssassin-3.0.0/sql/READMEIt wants you to load some .sql files (pretty standard), it wants connection details, and the module does teh rest for you.