That is two way of doing this ... first is to disable it ... second remove it.
First Method.
Run 'chkconfig --list | grep ldap'
You will see a list from 0 - 6. Note down the respective number which has the "on" attached behind. Lets say you have 2, 3 and 4 with on.
Then run 'chkconfig --level 234 off'
That should disable the service.
Second method.
Run 'rpm -qa | grep openldap'
That will give you a list of package with openldap as part of the filename. Note the name that include the"server" as part of the filename.
then run something like this
rpm -e openldap-servers-2.0.23-4
That would uninstall the software.