Whilst installing SharePoint 2013 the other day I found a very useful bit of PowerShell which will disable the loopback check.
$regKeyPath = "HKLM:\System\CurrentControlSet\Control\Lsa"
$key = "DisableLoopbackCheck"
New-ItemProperty -Path $regKeyPath -Name $key -Value "1" -PropertyType dword
It should be remembered that disabling the loopback check should only be done in certain scenarios. It is certainly not recommended on Production machines.
