All hail Lee Holmes - This is his Test-PSRemoting function

gistfile1.txt

function Test-PsRemoting 
{ 
# Written by Lee Holmes - http://www.leeholmes.com/blog/2009/11/20/testing-for-powershell-remoting-test-psremoting/
    param( 
        [Parameter(Mandatory = $true)] 
        $computername 
    ) 
    
    try 
    { 
        $errorActionPreference = "Stop" 
        $result = Invoke-Command -ComputerName $computername { 1 } 
    } 
    catch 
    { 
        Write-Verbose $_ 
        return $false 
    } 
    
    ## I've never seen this happen, but if you want to be 
    ## thorough.... 
    if($result -ne 1) 
    { 
        Write-Verbose "Remoting to $computerName returned an unexpected result." 
        return $false 
    } 
    
    $true    
}