Hm, I'm surprised this isn't included Out-Of-The-Box.  Let's say I have a new deployment of machines and I need to set the ExecutionPolicy for each of them.  Now, assuming I'm a domain admin, I should be able to do it remotely:

Function Enable-PowerShell {
    param (
        [string]$computerName = $env:computerName,
        [string]$mode = 'Unrestricted'     );
   
   
$modeHash = @{
        'Unrestricted' = 'Unrestricted';
        'RemoteSigned' = 'RemoteSigned';
        'AllSigned' = 'AllSigned';
        'Restricted' = 'Restricted';
        'Default' = 'Default';
        'Bypass' =  'Bypass'
    };
   
    if (!$modeHash[$mode]) {
        Write-Warning ("-mode $mode is not valid.  Valid modes are {0}" -f [string]::Join(", ", $modeHash.Keys));
        return $null;
    }
    $mode = $modeHash[$mode];
   
   
trap { continue; }
     
    $reg = [Microsoft.Win32.RegistryKey]::OpenRemoteBaseKey('LocalMachine', $computerName);
    if (!$reg) {
        Write-Warning "Unable to open remote registry on $computerName.";
        return $null;
    }
   
   
$key = "SOFTWARE\Microsoft\PowerShell\1\ShellIds\Microsoft.PowerShell";
    $regKey= $reg.OpenSubKey($key, $true);
    if (!$regKey) {
        Write-Warning "Unable to open registry key $key on $computerName.";
        return $null;
    }
   
   
$regkey.SetValue('ExecutionPolicy', $mode);
    if ($regkey.GetValue('ExecutionPolicy') -ne $mode) {
        Write-Waring "Unable to set PowerShell Execution Policy on $computerName to $mode";
         return $null;
    }
}