Preparing a Linux box for Oracle Clusterware and RAC installation is made fast and simple with the help of the Oracle Validated Rpm. Downloading and installing the rpm that match you Linux Kernel, automatize the install of the numerous components required to setup OCW and RAC on Linux.
http://blogs.oracle.com/AlejandroVargas/Installing-the-Oracle-Validated-rpm-on-EL5.pdf
http://blogs.oracle.com/AlejandroVargas/Installing-the-Oracle-Validated-rpm-on-EL5.pdf