What's the easy way to do this?
yum list installed
will show you if it's installed.
will show you if the service is running (might be called slapd)
Config will be somewhere like /etc/openldap/* and you can see if it's been configured.
Test it by querying it with something like:
ldapsearch -x -b 'dc=mycompany,dc=com' 'objectclass=*'
but you might have to know how it's (supposed to be) configured to know what to search for.