While both APIs allow access to LDAP servers from Java, they do it in very different ways.
The Novell JLDAP stuff really maps much closer to LDAP itself than any of the other LDAP APIs for Java. Among other things it will give you the ability to have finer controls over searches, controls used, etc...than most other LDAP APIs (including JNDI, though Java 1.4.1 closes the gap on this somewhat, though not completely).
http://www.mentata.com/ldaphttp/
Jon Roberts www.mentata.com