Oracle is providing to options, for corporate users you can connect to the Linux Support program by paying a fee towards Oracle. If you are not and just using the system for your home server for example you can connect to the public YUM server from Oracle. To be able to connect your system to the public yum server you have to simply take the following action:
# cd /etc/yum.repos.d
# wget http://public-yum.oracle.com/public-yum-el5.repo
After this you have to open the downloaded file in vi and make sure that you enable the channels you want to use for updating from the public Yum server. To enable one you have to set enabled=1 instead of enabled=0.
now you use the yum command to upgrade, update and install new software to your system. The great plus for Yum is that dependencies are taken care of and downloaded and installed when needed instead of turing your day into a dependency solving nightmare.