Beyond suggesting that you attend a course (I'm running a relevant course, online, in a couple of weeks) I don't see how a forum can answer such a huge question.
This sounds like a project of some size, specially when considered with the other question you posted. Many organizations, no matter how competent their on-site staff are, do like to bring in some outside assistance to help in such circumstances: this will usually reduce the time, cost, and disruption. There would be no shame in informing your management that you need some consultancy support for this exercise.
Oracle Certified Master DBA
Edited by: JohnWatson on Feb 23, 2013 8:57 PM
OP's post has been edited into something completely different. Very odd. I stand by my response, though.
it depends what you need and mean 'to migrate'
if you just need to transfer data then use: expdp and impdp tools (IMO, the easiest), consider other things like external tables (if you have), tablespace remaping (possible since 11g), etc.
Another ways are:
- RMAN backup and recovery (you may reorganize this way RAC to single instance and vice verse)
- transportable tablespaces.
How about you actually read the RAC Installation guides. If you have the systems, get the guides and start testing. I installed and reinstalled many times so I completely understood how it works. Just getting someones "blog" on how they did it may not meet your environment or requirements. READ INSTALL TEST REPEAT