steps required to change organisations website Host

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.NET

Hi,
My organisation is changing its web sites domain Host.like form test.org to test.gov.in and also host of the web site.
we have taken the domain name and registered it.
Now we want to shift all our web site and data on to newly owned domain host.
our web server and data servers or residing on different IP's on our dell servers.
my question is what are the steps and procedures required to shift all these stuff smoothly.
our web server is currently running on IIS 7.Web sites or mostly developed using .Net.
we are using Sql server 2008 R2 database, and Windows server 2008 R2 Enterprise edition.

pls help.
thanks