There's a Fedora project called EPEL which hosts a set of additional packages that can be installed on top of various distributions such as Red Hat Enterprise Linux, CentOS, Scientific Linux and of course also Oracle Linux. These packages are not distributed by the distribution vendor and as such also not supported by the vendors (including Oracle) however for users that want to pick up some extras that are useful, it's very easy to do this.

All you need to do is download the EPEL RPM from the website, install it on Oracle Linux 5 or Oracle Linux 6 and run yum install or yum search to get the packages.

example : 
# wget http://download.fedoraproject.org/pub/epel/6/i386/epel-release-6-5.noarch.rpm

# rpm -ivh epel-release-6-5.noarch.rpm

# yum repolist
Loaded plugins: refresh-packagekit, rhnplugin
repo id                repo name                                          status
epel                   Extra Packages for Enterprise Linux 6 - x86_64      7,124

The folks that build these repositories are doing a great job at adding very useful packages. They are free, but also unsupported of course.