i'm not sure but if you're looking for sys admin advice maybe you be better served trying a forum specific to that. that said both ldap and active directory are similar enough to just do ldap; if you are using linux ldap is available through your package system. for everything else google is your friend.
Imagination is more important than knowledge "Albert Einstein"
I just want to use LDAP, can you please suggest me that from where should i start and which LDAP server i should use.
So, the first thing you need to do is to install an ldap server. If it is already installed and you are not the guy who installed it, then run for the person who installed it and ask the path where it is installed. openldap is a good free ldap server. When you install it, you will get the installation path. There is a sh file called slapd that needs to be run as root to start openldap.
Wasn't there a post similar to this one in the same forum?
Anyway, if you post your error or problem you are having, we could help you out a little more. Start with the ldapserver, and then start using the ldap connection. Please keep up with these posts, as there are other people who are interested in the results.