Upgrade 10204 RAC ( 2 node RAC on LINUX EL4 ) to 11g R2 RAC

Important Note : I will be publishing the Steps may be in next couple of days for installation steps of RAC on linux and then it will be upgraded to 11g R2 RAC.

My current setup is having 10204CRS and 10204 DB version. It is 2 node RAC running on EL4