Oracle Directroy Service Manager (ODSM) - is Java application (introduced in 11g OID/OVD) to manage OID and OVD.
a) ODSM is java application which runs on WebLogic Server (Managed Server - wls_ods1)
b) Oracle Directory Manager (tool to manage OID in 10g) is now deprecated in 11g OID.
c) ODSM uses JNDI to connect to OID & OVD
d) You can install and configure ODSM with OID/OVD during installation or later

How to find ODSM URL ?

Option 1 - $Fusion_Middleware_Home/ Oracle_Identity_Management_domain/ servers/ wls_ods/ data/ nodemanager/ wls_ods1.url

Option 2 - Identify Managed Server (wls_ods1) port and use URL http://host:port/odsm

How to access ODSM ?

1. Start Managed Server wls_ods1
startManagedWebLogic.sh wls_ods1

2. Access ODSM from URL - http://host:port/odsm where default managed server (wls_ods1) port is 7005 (cn=orcladmin)

Configuring YUM on OEL
When using Oracle Enterprise Linux the easiest way to install the required packages is to use Oracle’s public Yum server, http://public-yum.oracle.com.

There are a couple of quick steps to configure OEL to use Oracle’s Yum Server:
cd /etc/yum.repos.d
wget http://public-yum.oracle.com/public-yum-el5.repo

Open the yum configuration file in a text editor. Locate the section in the file for the repository you plan to update from,

e.g. [el5_u5_base]
Change enabled=0 to enabled=1

Begin using yum, for example:
$ yum list
$ yum install firefox