The openldap project has picked up the University of Michigan codebase
The ldapns is the nameservice libraries and scripts for using LDAP as a nameservice. It can be obtained from ftp://ftp.rage.net/pub/LDAP/ldapns-latest.tgz. Precompiled versions are available in several package formats. This software is only usefull for machines using PAM and nameservice-switch(GLIBC). Unpack the distribution using tar, then run 'make; make install'. Cross fingers. This should install the libraries and scripts in the appropriate places on your system.
Netscape is in the process of porting their directory server to Linux. By the time you read this it may be available. See http://www.netscape.com/ for more information.