I have composed (and am maintaining) a fairly extensive presentation on LDAP, OpenLDAP, and integration with various services. ldapv3.pdf (ftp://kalamazoolinux.org/pub/pdf/ldapv3.pdf) hosted by the Kalamazoo Linux Users Group (http://www.kalamazoolinux.org). (Kalamazoo, Mi. USA) This included a section on Turba.
An open, cross-platform journaling program.
A scientific plotting package.