function Bindings(){ 
    return [System.Reflection.BindingFlags]::CreateInstance -bor 
    [System.Reflection.BindingFlags]::GetField -bor 
    [System.Reflection.BindingFlags]::Instance -bor 
    [System.Reflection.BindingFlags]::NonPublic; 
} 

function GetFieldValue([object]$o, [string]$fieldName){ 
    $bindings = Bindings; 
    return $o.GetType().GetField($fieldName, $bindings).GetValue($o); 
} 
function ConvertTo-UnsecureString([System.Security.SecureString]$string){  
    $intptr = [System.IntPtr]::Zero; 
    $unmanagedString = [System.Runtime.InteropServices.Marshal]::SecureStringToGlobalAllocUnicode($string); 
    $unsecureString = [System.Runtime.InteropServices.Marshal]::PtrToStringUni($unmanagedString); 
    [System.Runtime.InteropServices.Marshal]::ZeroFreeGlobalAllocUnicode($unmanagedString); 
    return $unsecureString; 
} 
Get-SPManagedAccount | % { "$($_.UserName): $(ConvertTo-UnsecureString (GetFieldValue $_ 'm_Password').SecureStringValue)" }