All about SQL Server with 32bit to 64bit cluster migration - steps to take care

Recently there has been few 'interesting' posts that will help most of the SQL Server users in this cyber world. Here is the basic question posted by the user:
I have been tasked with migrating our SQL Server 05 Active/Passive cluster from 32bit to 64bit with as little downtime as possible. What is the best method of this. Can I just build one node and swap it out having a 32bit node and 64bit node attached or do I have to build both nodes and just reattach/restore the databases after the cluster is built?
Pretty scary isn't it, no much time to test the implementations without knowing the implications as there was no development environment.
Eventually the user was able to upgrade (this mammoth task) based on the references available on web - for more read on this interesting task review ThisForum post.

The migration or upgrade from 32bit to 64 bit is no different, as in this case you have to test your application functionality and their drivers, refer to this http://sqlserver-qa.net/blogs/tools/archive/2008/01/22/upgrade-blurg.aspx link for further information on FAQ upgrade.