How to configure failover and load balancing in 11gR2 RAC in Red Hat Linux..?
The RAC environment is ready for two node RAC.
if you already have your RAC environment as the wording suggests then the "failover" part is what RAC does the best, it is part of RAC functionality to "failover" when a node goes down.
In regards to load balancing you can either go for round-robin or functional load balancing. 10gR2 comes with Load Balancing Advisory to help with the first but you have to do it yourself if you want to go for functional load balancing. As you may know the infamous interconnect is RAC's Achiles heel and you do not want to create over it more traffic that extrictely needed, that's way "intelligent" or "functional" load balancing is a pretty good idea but only you know your users and your queries so to group users that do similar jobs to hit the same nodes - you can do this via TNS.
Disclaimer: Advice is provided to the best of my knowledge but no implicit or explicit warranties are provided. Since the advisor explicitly encourages testing any and all suggestions on a test non-production environment advisor should not held liable or responsible for any actions taken based on the given advice.