Well when you have multiple websites with multiple host headers, it would normally take a while to transfer host headers to a new group of websites. With the Powershell script below, this can achieved with very little set-up.
Note - Sadly the formatting (like indentation) has been lost in the post.
## Written by Ashley Poole ##
## Description - Dynamically swaps host headers from the source website to destination website. The script will suffix the host heads on the resource website with '.reallocated.ps'. This script was written to easy the deployment of new websites during major releases ##
## Warning - This script will delete all bindings on the new website before copying others from the old website ##
# Create 2D array of source and destination website names objects
[array] $Websites = @ (@ ( "SourceWebsite1", "DestinationWebsite1" ),@ ( "SourceWebsite2", "DestinationWebsite2" ))
# Name suffix for old Host Headers
$SourceHostHeaderSuffix = ".reallocated.ps"
# Looping through website pairs and migrating host headers
foreach ( $Website in $Websites )
# ** If we need to rollback host headers, Simply run this script again but swap $Website and $Website around **
$SourceWebsiteName = $Website 
$DestinationWebsiteName = $Website 
Write-Host "Evaluating Website: " $SourceWebsiteName "/" $DestinationWebsiteName -ForegroundColor Yellow
$Bindings = Get-WebBinding -Name $SourceWebsiteName | Select bindingInformation
# Remove all binding on the new website in preparation
Get-WebBinding -Name $DestinationWebsiteName | Remove-WebBinding
# Looping through each binding on from the current $website basis
foreach ( $Binding in $Bindings )
$BindingBreakdown = $Binding.bindingInformation -split ( ":" )
# Breaking down items from the array to make them readable latter in script
$BindingIPAddress = $BindingBreakdown 
$BindingPort = $BindingBreakdown 
$BindingOrginalHostHeader = $BindingBreakdown 
$BindingSourceHostHeader = $BindingBreakdown 
$BindingDestinationHostHeader = $BindingBreakdown 
Write-Host "Evaluating Binding:" $BindingOrginalHostHeader
# Checking if $BindingSourceHostHeader was already renamed (I.e contains value in $SourceHostHeaderSuffix). If so we need to reverse the process.
If ( $BindingSourceHostHeader -contains $SourceHostHeaderSuffix )
$BindingDestinationHostHeader = $BindingDestinationHostHeader -replace $SourceHostHeaderSuffix, ""
$BindingSourceHostHeader = $BindingSourceHostHeader + $SourceHostHeaderSuffix
$BindingInformation = $BindingIPAddress + ":" + $BindingPort + ":" + $BindingOrginalHostHeader
# Renaming old binding
Set-WebBinding -Name $SourceWebsiteName -BindingInformation $BindingInformation -PropertyName HostHeader -Value $BindingSourceHostHeader
# Add new binding
New-WebBinding -Name $DestinationWebsiteName -Protocol http -IPAddress $BindingIPAddress -Port $BindingPort -HostHeader $BindingDestinationHostHeader
Write-Host "Completed Binding:" $BindingOrginalHostHeader
Write-Host "Completed Website:" $SourceWebsiteName "/" $DestinationWebsiteName -ForegroundColor Yellow
, DevOps with DevOps : PowerShell, IIS