The installation of OEL5.3 is pretty similar of the previous version.
Two main differences however :
1. We have now a DVD iso image available for download (http://edelivery.oracle.com)
2. We have an Oracle specific package (oracle-validated-1) to check some settings and create the oracle user and dba/oinstall groups :
All the other steps are same as the previous version, I won't paste the screenshots again over here.
You can find all the screenshots of the OEL4.6 install in one of my previous posts :