gistfile1.ps1

param (
    #folder where all your websites are located
    [string]$webSiteRootFolder = "c:\websites",
    #name of site that you're setting up
    [string]$siteName = "HelloWorldSite",
    #the port your default binding is using
    [string]$port = 8090,
    #where the source files are
    [string]$Sourcefiles = "source/*"
)

import-module WebAdministration (1)

#site folder
$siteInstallLocation = "$webSiteRootFolder\$siteName"
#site application pool
$siteAppPool = "$siteName-pool"
#check if the site is already present (determines update or install)
$isPresent = Get-Website -name $siteName (2)

if($isPresent){
  #upgrade the current package
  Write-Host "$siteName will be updated"
  Copy-Item $Sourcefiles -Recurse $siteInstallLocation -Force
}else{
  #install a clean version of the package
  Write-Host "$siteName will be installed"
  #create site folder
  new-item $siteInstallLocation -ItemType directory -Force (3)
  #copy site files to site folder
  Copy-Item $Sourcefiles -Recurse $siteInstallLocation -Force (4)
  #create application pool
  New-WebAppPool -Name $siteAppPool -Force (5)
  #set the alwaysRunning setting to true.(this is needed for workflow to start properly)
  #to find which path to modify look in the applicationHosts.config file (google for location)
  Set-WebConfigurationProperty "/system.applicationHost/ApplicationPools/add[@name='$siteAppPool']" -PSPath IIS:\ -Name startMode -Value "AlwaysRunning" (6)
  #create site
  New-Website -Name $siteName -Port $port -ApplicationPool $siteAppPool -PhysicalPath $siteInstallLocation (7)
}